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2018 Spring Meeting



Carrier transport, photonics and sensing in group IV-based and other semiconductors nano devices

The new composites and nanostructures of group IV materials provide a platform for advanced devices for Nanoelectronics, Photonics and Sensors. The symposium will focus on group IV materials, nanostructures and related devices with the objective to bring together scientists working in different application fields.


The scope of the proposed symposium will include experimental and theoretical innovations related to group IV nanoelectronics, nanophotonics and nanosensing. An emphasis will be made on high mobility materials suitable for fast devices, light emission and light absorption.

These topics have attracted an increasing attention in the recent years for various applications, including infrared communication and imaging. The very critical issues are therefore carrier transport properties and lifetimes which will be reflected in the symposium program.

The photonic devices of particular interest are detectors, light emitting sources, waveguides, optical modulators and CMOS devices. Additional topics in the symposium scope are defect characterization, engineering and the impact of crystal quality on the properties of electronic and photonic devices.

Moreover, integrated photonic devices are recently emerging in the field of biological and chemical sensing allowing ultra-high sensing performances and efficient CMOS-compatible systems.

Simulations and calculations of nanodevices, predicting their physical properties and performances are vital to successful device design and optimization. This is particularly important when novel Si-Ge-Sn-C alloys and structures are involved; and in case of nano scale devices, where conventional approximations can no longer be applied.

The symposium will bring together the whole chain starting with novel technological developments in the field of material synthesis; subsequently, material characterization, device design and fabrication; and finally, device characterization, simulation and modeling. New applications will be welcome as well.

Hot topics to be covered by the symposium:

  • Fabrication and characterization of group IV nanostructures, nanodevices and nanosensors
  • Carrier transport in nanodevices
  • Optoelectronic materials and nanodevices using Si-based heterostructures and nanostructures
  • Integration of photonics with Si CMOS technology
  • Strain band-gap engineering and carrier transport in CMOS
  • Si-based optical modulators, switches and detectors
  • Si-based waveguide technology and nanodevices
  • Luminescence in Si-based materials
  • Photonic crystals
  • Integrated waveguide sensing
  • Nanomaterials for life science applications
  • Nanoscale biosensors
  • Defect engineering and characterization

List of confirmed invited speakers:

  • Jun Luo, (Chinese Academy of Science) China: Integration of advanced high-k/metal gate stack in nano-scaled transistors
  • Eddy Simeon, (IMEC) Belgium: The effect of defects on transport in nanodevices
  • Douglas Paul, (Glasgow University) UK: Ge and GeSn nanophotonic devices for mid-infrared sensing
  • Steve Koester, (University of Minnesota) USA: 2D materials for nanoelectronics, nanophotonics and nanosensing
  • Philippe M. Fauchet, (Vanderbilt University) USA: Electrical and optical silicon-based biosensors
  • Maksym Myronov, (The University of Warwick) UK: Epitaxy of advanced group IV alloys for nanodevices
  • Xue Feng, (Tsinghua University) China: Photonic Integrated Devices for Optical Vortices
  • Yakov Roizin, (TowerJazz & Tel Aviv University) Israel : VLSI scaling roadmap and integration of novel materials with silicon
  • Wolfgang Skorupa (Helmholtz-Zentrum Dresden-Rossendorf) Germany: Advanced thermal processing of group-IV materials and beyond
  • Maria Josè Lo Faro (University of Catania) Italy: Silicon Nanowires: the route from synthesis towards applications

Tentative list of scientific committee members:

  • Mehmet Ozturk, (NC State University) USA
  • Matty Caymax, (IMEC) Belgium
  • Andrej Kuznetsov, (University of Oslo) Norway
  • Tian-Ling Ren, (Tsinghua University) China
  • Yuji Yamamoto, (IHP) Germany
  • Dimitris Tsoukalas, (National Technical University of Athens) Greece
  • Peter Pichler, (Fraunhofer IISB) Germany
  • Rasit Turan, (Middle East Technical University) Turkey
  • Lisik Zbigniew (Technical University of Lodz) Poland
  • Guilei Wang, (Chinese Academy of Science) China
  • Slotte Jonatan, (Aalto University) Finland
  • Wei.Xin Ni, (Linköping University) Sweden
  • Lis Nanver, (University of Twente) The Netherlands
  • Aleksey Andreev, (Hitachi Cambridge Laboratory) UK
  • Renong Liang, (Tsinghua University) China
  • Jan Linnros, (KTH Royal Institute of Technology) Sweden
  • Luca Maresca, (University of Napoli Federico II) Italy
  • Chao Zhao, (Chinese Academy of Science) China
  • Rick Wise, (University of Arkansas) USA


Manuscripts will be published in a reputable and refereed journal: Materials Science Journal: Materials in Electronics, Springer.

Graduate Student awards:

Five selected member of scientific committee will rank independently the work of young scientists. Top 3 presentations/posters will be critically reviewed and a winner will be selected.


  • EpiLuvac, Lund, Sweden
  • Nocilis Materials, Stockholm, Sweden
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Session 1: Group IV materials for photonic application : A. Irrera
Authors : Maksym Myronov
Affiliations : Department of Physics, The University of Warwick, Coventry CV4 7AL, UK

Resume : In the recent years, the epitaxy of group IV semiconductors was advanced by appearance of new family of alloys grown by an industrial type Chemical Vapour Deposition (CVD) technique on standard Si substrate. They substantially expanded functionality of existing Si based materials and devices. The first one is the GeSn alloy, which is a natural expansion of the SiGe family material beyond pure Ge into the territory of traditional III-V compound semiconductors like GaAs and InGaAs. Adding Sn to relaxed Ge, leads to transformation of Ge indirect bandgap to direct one in the narrower band gap GeSn alloys with Sn content above ~8%. It has already led to demonstration of efficient light emission beyond 3 um, in the mid-IR spectrum range, and outlined pathway for the realization of the long awaiting light source and potential laser on the Si platform. More recently, strained GeSn epilayers exhibited very promising materials properties, which also opens opportunity for their potential application in wide range of electronic and spintronic devices. Another material is cubic silicon carbide (3C-SiC). It is the only one, among over 200 SiC polytypes, which can be grown epitaxially on Si. Recently, novel low-temperature epitaxy technology resulted in invention of a long awaiting state of the art wafer scale heteroepitaxy of 3C-SiC on standard Si substrate. The 3C-SiC on Si offers an alternative wide bandgap semiconductor to conventional materials such as hexagonal 4H-SiC or 6H-SiC and GaN for detection of UV light, applications in RF and power devices, and sensors for harsh environment, which also can be integrated with other know materials and devices on the Si platform.

Authors : M. Bertrand, Q. M. Thai, N. Pauc, R. Khazaka, J. Aubin, J. Chrétien, F. Armand Pilon, H. Sigg, A. Chelnokov, J.M. Hartmann, V. Calvo, V. Reboud
Affiliations : Univ. Grenoble Alpes, CEA-LETI, Minatec, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-INAC, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-INAC, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-LETI, Minatec, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-LETI, Minatec, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-INAC, 17 rue des Martyrs, 38000, Grenoble, France; Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232, Villigen, Switzerland; Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232, Villigen, Switzerland; Univ. Grenoble Alpes, CEA-LETI, Minatec, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-LETI, Minatec, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-INAC, 17 rue des Martyrs, 38000, Grenoble, France; Univ. Grenoble Alpes, CEA-INAC, 17 rue des Martyrs, 38000, Grenoble, France;

Resume : Direct band-gap light emission in the infra-red can be achieved in GeSn provided that the Sn content is high enough. Here, we investigate the lasing of optically-pumped GeSn micro-disks with 16% of Sn and study the impact of SiGeSn barriers. Our aim is to reduce lasing threshold and ultimately fabricate an electrically pumped GeSn laser. Three versions of GeSn / SiGeSn heterostructures were deposited at low temperature with a 200mm Epi Centura 5200 RPCVD tool. All three comprised a high-Sn-content, thick GeSn optically active layer. In 1st structure, we used a strain-relaxed Ge buffer (SRB). In the 2nd one, a step-graded GeSn buffer was added on top of the Ge SRB. In the 3rd structure, additional SiGeSn confinement layers were added on top and bottom of the optically active SiGeSn layer of the previous, second structure. We developed selective recipes that etch Ge much faster than GeSn and fabricated micro-disk optical cavities. The micro-disk lasers were tested under optical nanosecond pulsed laser pump at wide temperature range. The 3rd configuration shows significantly reduced lasing thresholds. The measured bandgaps are in a good agreement with the predictions of our 8-bands k.p model using Van de Walle theory for band alignment. From this model describing confinement in conduction and valence bands, we foresee that combining high-Sn-content GeSn layers, proper strain control, and SiGeSn confinement barriers, may reduce lasing threshold and improve working temperature.

Authors : Søren Roesgaard(1), Leopold Scheffler(2), Etienne Talbot(3), Quentin Ramasse(4), Jacques Chevallier(1,2), John L. Hansen(1,2), and Brian Julsgaard(1,2).
Affiliations : (1) Interdisciplinary Nanoscience Center (iNano), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.; (2) Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark.; (3) Groupe de Physique des Matériaux, Université et INSA de Rouen, UMR CNRS 6634, av. de l’Université, 76800 Saint Etienne du Rouvray, France.; (4) SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury, Warrington WA4 4AD, United Kingdom.

Resume : Group-IV-based semiconductor nanostructures are very interesting candidates for optoelectronic devices that can potentially be integrated into the current silicon framework. Light emission from silicon containing tin-nanocrystals, formed by post-growth annealing, has previously been demonstrated. Here we present correlations between optical, electrical, and structural characterization in order to better understand the mechanisms behind the light emission that is highly dependent on the annealing temperature. The many complementary analysis methods allow for a more detailed discussion on these mechanisms and how to potentially utilize them for future devices.

Authors : R. Milazzo,(1) G. Impellizzeri,(2) A. La Magna,(3) D. Scarpa,(4) S. Boninelli,(2) J. Frigerio,(5) A. Ballabio,(5) C. Carraro,(1) A. Sanson,(1) D. De Salvador,(1) A. Andrighetto,(4) A. Portavoce,(6) D. Mangelinck,(6) J. Slotte,(7) M. Ortolani,(8) G. Isella,(5) G. Fortunato,(9) A. Carnera,(1) and E. Napolitani(1)
Affiliations : (1) Dipartimento di Fisica e Astronomia, Università di Padova and CNR-IMM, Via Marzolo 8, I-35131 Padova, Italy; (2) CNR-IMM, via S Sofia 64, I-95123; (3) CNR-IMM , Z.I. VIII Strada 5, 95121 Catania, Italy; (4) Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (PD), Italy; (5) L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I-22100 Como, Italy; (6) IM2NP, CNRS-Universités d’Aix-Marseille et de Toulon, Faculté de saint Jérôme, 13397 Marseille, France; (7) Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076 AALTO, Finland; (8) Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy; (9) CNR-IMM, Via del Fosso del Cavaliere 100, 00133 Roma, Italy;

Resume : Germanium recently attracted a renewed interest in various fields of material science such as photonics, opto- and nano-electronics, owing to its high carrier mobility as well as to its compatibility with silicon technology. However, Ge-based devices often requires well-defined doping profiles and very high activation levels (>1020cm-3), which are challenging for most of dopants due to their high diffusivity and low solubility . For this purpose, ion implantation followed by pulsed laser melting (PLM) is the most promising technique as it induces ultra-fast liquid phase epitaxial regrowth that allows confinement of diffusion while enhancing dopant incorporation. Latest studies on p- (by means of B or Al) and n-type (P, As) doping by PLM following ion-implantation into bulk Ge or Ge-on-Si epilayers will be presented. Thanks to advanced chemical (1D and 3D), electrical and structural characterizations with nanometer resolution, fundamental mechanisms such as non-equilibrium segregation, diffusion, clustering, strain and defects evolution will be discussed with special care on strategies for improving the electrical activation, together with issues about contaminations and thermal stability.

Authors : Guilei Wang1,2*, Jun luo1,2, Renrong Liang3, Binbin Jiao1, Shichang Yun1, Yanpeng Hu1, Jinjuan Xiang1, Hushan Cui1, shihao Gu1, Zhenzhen Kong1, Jiahan Yu1, Jinbaio Liu1, Tao Yang1, Junfeng Li1, WenWu Wang1,2, Chao Zhao1,2, Tianchun Ye1,2and Henry H. Radamson1,2,4*
Affiliations : 1 Key laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People’s Republic of China; 2 University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China; 3 Tsinghua National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084, People's Republic of China; 4 KTH Royal Institute of Technology, Brinellv. 8, 10044 Stockholm, Sweden

Resume : Integration of Ge material in various electronic and photonic device is growing fast during the recent years. This is due to excellent properties e.g. high hole mobility for pMOS and direct bandgap behavior (at Γ-point) for photodetectors operating at 1.5 µm for telecom application. In this study, we present the process to form single crystal of 8-inch strained Ge-on-insulator (sGOI) with surface roughness below 1nm and high quality on 200mm Si wafers. The wafers were manufactured by wafer bonding followed by mechanically grinding and chemical mechanical polishing (CMP) process. The Ge epitaxy was carried out by reduced pressure chemical vapor deposition system (RPCVD), where a cyclic annealing treatment could decrease the defect density to below 105 cm-2. The bonding is to SiO2 substrate but the surface of wafers was treated with O3 and a layer of Al2O3 was deposited by Atomic Layer Deposition (ALD). The results showed that the bonding process is sensitive to Ge surface roughness, thermal oxide thickness, applied force, and thermal annealing. Finally, the thickness of Ge was determined by CMP where uniformity was a crucial issue. The bandgap of sGOI could be tuned by the amount of applied mechanical force during the bonding as well as by changing the thickness of Ge layer. As a result, the lattice constant of Ge is distorted and the bandgap wavelength shifts from 1.5 µm to as high as 1.8 µm in this study. The sGOI can be used to manufacture for both vertical and lateral photodetectors. The other goal of this study were to manufacture sGOI wafers for high mobility transistors when a thin layer of Ge is used as channel material. For the transistor application, a combination of wet/dry etch and CMP was used to decrease the Ge layer thickness below 100nm. The GOI wafers were characterized by photoluminescence (PL), high-resolution transmission electron microscopy (HRTEM), Hall measurement, and high-resolution x-ray diffraction techniques (HRXRD). Acknowledgement This work was financially supported by “National S&T Major Project 02”, the opening project of Silicon Based High Mobility Materials and Devices Integrated Technology, (Project No. 2011ZX02708-005) and “National Key Research and Development Program of China” (2016YFA0301701), which are acknowledged.

Authors : Ivan Marri, Salvo Mirabella, Antonio Terrasi and Stefano Ossicini
Affiliations : Ivan Marri: CNR-Istituto di Nanoscienze-S3, via Campi 213 A, I-41125 Modena, Italy Salvo Mirabella: MATIS IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, Catania, Italy Antonio Terrasi: MATIS IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, Catania, Italy Stefano Ossicini: Università degli Studi di Modena e Reggio Emilia, Dipartimento di Scienze e Metodi dell'Ingegneria, via Amendola 2, Reggio Emilia, Italy

Resume : In this talk we present theoretical results obtained in the study of dense arrays of Ge nanocrystal (NCs). By exploiting methods based on the Density Functional Theory and on the Time Dependent Density Functional Perturbation Theory, we investigate effects induced by NCs interplay on both electronic and optical properties of Ge NCs. In particular, we report a set of results obtained in the calculation of the absorption spectra of different systems of interacting Ge NCs, where NCs interplay and wavefunction delocalisation are tuned by changing the reciprocal NC-NC separation. Finally, theoretical results are compared with the ones obtained in experiments conducted on Ge NCs organised in a dense array and incapsulated in a SiO2 matrix.

Session 2: Group IV photonic devices : H. H. Radamson
Authors : R.W. Millar 1, K.F. Gallacher 1, D. Dumas 1, U. Griskeviciute 1, P. Jahandar 2, A. Ballabio 3, J. Frigerio 3, L. Baldassarre 4, M. Myronov 2, G. Isella 3, M. Ortolani 4, D. Brida 5, P. Biagioni 6, and D.J. Paul 1
Affiliations : 1 University of Glasgow, School of Engineering, Rankine Building, Oakfield Avenue, Glasgow, G12 8LT, U.K.; 2 University of Warwick, University of Warwick, Department of Physics, Coventry, CV4 7AL, U.K.; 3 Politecnico di Milano, L-NESS, Dipartimento di Fisica, Polo di Como, Via Anzani 42, I-22100 Como, Italy; 4 Sapienza Universita ́ di Roma,Dipartimento di Fisica, Piazzale Aldo Moro 5, I-00185 Rome, Italy; 5 Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany; 6 Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 30, I-20100 Milan, Italy;

Resume : In the last decade there has been a shift of focus of the Si photonics community to the mid-infrared (MIR), with an emphasis on sensing applications, due to unique molecular absorption lines across the 2-13 µm range. For such applications, Ge, SiGe and GeSn are well suited materials, due to compatibility with Si foundry processes, and transparency up to ~15 µm wavelength for integrated passive components. Nano and micro-photonic structures on these platforms can potentially leverage the ubiquity of Si foundries to facilitate the production of low cost MIR photonic circuits, with applications in health-care, pollution monitoring, and defence. Here, we investigate a range of photonics components, which could serve as the building blocks to mid-infrared photonic circuits on a Si platform. Low-defect, pseudomorphic GeSn alloys grown on Ge epilayers are strain engineered with high stress silicon nitride. This results in highly direct bandgap, tensile strained Ge0.893Sn0.107/Ge µ-disks emitting above 3 µm wavelength, with an overlap with methane absorption lines. Activated doping densities of ~8e19 cm-3 in laser annealed n++-Ge epilayers shift the plasma-edge into the MIR, allowing for plasmon modes to be supported across the full 8-13 µm sensing window in etched nano-antennas. Such structures demonstrate resonantly enhanced absorption of a toxic gas simulant. Absorption from p-Ge/SiGe multiple quantum well structures is demonstrated from intersubband transitions in the valence band. The quantum well operating wavelength is tunable with well width; we demonstrate broadband absorption from 6-9 µm, covering acetone absorption lines. Finally, passive Ge on Si waveguides operating up to 11 µm wavelength are demonstrated for the first time.

Authors : E. Napolitani(1), R. Milazzo(1), C. Carraro(1), A. Ballabio(2), J. Frigerio(2), K. Gallacher(3), R. Millar(3), V. Giliberti(4), L. Baldassarre(4), L. Maiolo(5), A. Minotti(5), A. Pecora(5), F. Bottegoni(6), P. Biagioni(6), F. Mazzamuto(7), K. Huet(7), D. Scarpa(8), A. Andrighetto(8), D.J. Paul(2), M. Ortolani(4), and G. Isella(2)
Affiliations : (1) Dipartimento di Fisica e Astronomia, Università di Padova and CNR-IMM, Via Marzolo 8, I-35131 Padova, Italy; (2) L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, I-22100 Como, Italy; (3) School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT, United Kingdom; (4) Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy (5) CNR-IMM, Via del Fosso del Cavaliere 100, 00133 Roma, Italy; (6) Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy; (7) Laser systems and solutions of Europe (LASSE), SCREEN Semiconductor Solutions Co., Ltd., 14-38 rue Alexandre, Bldg D, 92230 Gennevilliers, France; (8) Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (PD), Italy

Resume : The integration of highly doped Ge on Si with a controlled amount of tensile strain is crucial for several applications in advanced nanoelectronic and photonic devices. However, obtaining n-type doping above 5x1019cm-3 and in-plane biaxial tensile strain above +0.2-0.25 % with conventional growth and annealing methods is highly challenging. Here we report on the combination of in‑situ doping of Ge-on-Si epilayers and pulsed laser melting (PLM) to improve the activation of phosphorous in germanium. Secondary ion mass spectrometry measurements indicate that the box-like profile of as-deposited epilayers is preserved during PLM with minimal P out-diffusion. By improving the growth and PLM conditions an activated uniform n-doping concentration well above 1x1020cm-3 over 2-300 nm thick layers has been achieved, as measured by infrared reflectivity and differential VdP-Hall. Photoluminescence demonstrates clear bandgap narrowing and an increased ratio of direct to indirect bandgap emission confirming the high doping densities achieved. Finally, High Resolution X-Ray Diffraction and Raman measurements show that, thanks to the extremely high thermal gradients achieved by PLM, the in-plane residual thermal strain is increased well above +0.3%, favoring the electron population of the gamma-valley.

Authors : Ching-Tsung Huang1, Yen Chuang1, Chia-You Liu1,a), and Jiun-Yun Li1,2,3
Affiliations : 1Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan; 2Department of Electronical Engineering, National Taiwan University, Taipei, Taiwan; 3National Nano Device Laboratories, Hsinchu, Taiwan;

Resume : A direct-bandgap GeSn alloy is important for Si photonics due to the capability of efficient light emission and the compatibility to Si VLSI technology. The transition between indirect and direct bandgaps in strained GeSn occurs at a Sn fraction of 9 ~ 12 % [1][2]. For relaxed GeSn, the transition was predicted to occur at a lower Sn fraction of 6.5 ~ 11 % [3][4]. In this work, we present photoluminescence (PL) spectra of strained Ge0.88Sn0.12 and relaxed Ge0.92Sn0.08 at 300 K~16 K. At room temperature, only the Γ-band luminescence was observed. As the temperature is below 150 K, the L-band luminescence could be observed along with the Γ-band luminescence. This suggests that the indirect-direct bandgap transition in strained and relaxed GeSn occurs at ~ 12 and ~ 8 %, respectively. Furthermore, we performed the low-temperature PL measurements on the Ge/Ge0.92Sn0.08/Ge and Ge/Ge0.90Sn0.10/Ge quantum well structures. The effective bandgaps are larger than those in the bulk GeSn materials due to the quantum effects. A detailed calculation on the PL peak positions based on the transmission-electron-microscopic (TEM) and reciprocal space mapping (RSM) data was performed and well matched with the experimental results. [1] S. A. Ghetmiri et al., APL, 105, p. 151109, 2014. [2] H. S. Mączko et al., Scientific Reports, 6, p. 3, 2016. [3] S. Gupta et al., JAP, 113, p. 073707, 2013. [4] K. L. Low et al., JAP, 112, p. 103715, 2012.

Authors : C. Carraro(1), R. Milazzo(1), F. Sgarbossa(1,2), G. Maggioni(1,2), W. Raniero(2), S. Carturan(1,2), D. Scarpa(2), L. Baldassarre(3), M. Ortolani(3), A. Andrighetto(2), D.R. Napoli(2), D. De Salvador(1,2) and E. Napolitani(1,2)
Affiliations : (1) Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova, Italy; (2) Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (PD), Italy; (3) Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy

Resume : The fabrication of highly doped and high quality Ge layers is currently a challenging and hot topic in nanoelectronics, photonics and radiation detectors. We explore for the first time n-type doping of Ge by sputter deposition of a thin layer of pure Sb on the Ge surface followed by pulsed laser melting (PLM) diffusion annealing cycles. A broad characterization has been performed, based on secondary ion mass spectrometry, channeling-Rutherford backscattering spectrometry, Van der Pauw-Hall, high resolution x-ray diffraction, infrared reflectivity, scanning electron microscopy. We show that PLM promotes an efficient diffusion of high Sb concentrations in the Ge melted subsurface layer, followed by an ultra-fast epitaxial regrowth. As a result, excellent surface morphology and crystalline quality is obtained, with record active Sb concentrations well above 1020cm-3 over 100-150 nm. Key properties such as substitutional fraction, electron mobility, residual strain, infrared reflectivity and plasma frequency are also characterized and discussed. These results demonstrate Sb deposition followed by PLM as a simpler and cheaper doping method, and with lower thermal budget, than the other methods commonly employed such as ion implantation or in-situ doping of Ge epilayers, and at the same time able to achieve record activation levels with no residual damage and excellent electrical and optical properties, relevant for Ge based future advanced devices.

Authors : M. Stepikhova, A. Yablonskiy, E. Skorokhodov, A. Novikov, M. Shaleev, S. Sergeev, D. Utkin, Z. Krasilnik
Affiliations : Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhny Novgorod, Russia; Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia; 3Institute of Semiconductor Physics, Siberian Branch of RAS, Novosibirsk, Russia

Resume : GeSi structures with self-assembled islands are promising candidates for devices of Si photonics due to their emission in the spectral range 1.3-1.6 m. Embedding of islands into a microcavity can provide a substantial increase in the radiative recombination efficiency and allow control of the island-related emission. In this contribution the luminescent properties of various photonic crystal (PhC) microcavities with Ge(Si) islands will be discussed. A series of 2D PhCs with a L3-type microcavity, as well as without a microcavity, were fabricated in GeSi/SOI structures with nanoislands by e-beam lithography and ICP/RF plasma etching. The parameters of the PhCs were chosen in such a way that the island-related emission band overlapped with the resonant wavelengths of the PhCs with L3 cavity, or with the low group velocity modes near the gamma point of the reciprocal lattice for the PhCs without a microcavity. A strong enhancement of the room-temperature island-related photoluminescence has been observed both for the PhCs with L3 defect (resonant enhancement) and without defect (non-resonant enhancement). The non-resonant enhancement was characterized by specific features in the PL spectra reflecting the distribution of the low group velocity modes of the PhCs. The role of the Purcell effect and an increase in the light extraction efficiency on the luminescence enhancement in the PhCs with Ge(Si) islands will be discussed. This work was supported by scientific programs of RAS.

Authors : Jacopo Frigerio, Giovanni Isella, Andrea Ballabio, Enrico Talamas Simola,
Affiliations : L-Ness, Dipartimento di Fisica del Politecnico di Milano, Polo di Como, Via Anzani 42, 22100 Como, Italy

Resume : The realization of fast, compact and yet low power consuming optical modulators is one of the key issues regarding the development of on-chip optical communications in silicon-based photonics. A viable solution might be offered by Ge/SiGe multiple quantum wells, as they show a strong quantum confined Stark effect (QCSE) which is suitable for electro-absorption modulation. Alongside low power consumption, another key advantage of Ge/SiGe quantum well structures is the possibility to tune the modulation wavelength over a wide range of values, spanning from about 1300 nm up to 1500 nm, by modifying well thickness, Ge concentration in wells and barriers and strain state of the structure. The efficiency of QCSE-based modulators can be further enhanced by substituting the standard quantum well with more “exotic” structures, such as coupled quantum wells, whose separate confinement of electrons and holes allows for high modulation even at low applied electric fields, significantly enhancing modulation efficiency. Finally, strong variations in the absorption spectra induce a remarkable electro-refractive effect as well as the electro-absorption effect, which can be employed to realize a phase modulator. For a given quantum well structure the electro-refractive effect works at longer wavelengths than the electro absorption, further extending the spectral range of operation of QCSE-based modulators.

Authors : D.V. Yurasov, P.A. Yunin, M.N. Drozdov, N.A. Baidakova, A.N. Yablonskiy, P.A. Bushuykin, B.A. Andreev E.V. Skorohodov, A.V. Novikov
Affiliations : Institute for Physics of Microstructures RAS, Nizhny Novgorod, Russia

Resume : Today n-Ge/Si(00) structures are promising for silicon photonics and plasmonics applications. However, Ge layers having donor concentration considerably higher than its equilibrium solubility limit are necessary to achieve the desired optical properties. In this work we report about growth and optical properties of Ge:Sb/Si(001) structures with high electron concentration. Ge:Sb/Si(001) layers with 0.2-0.25% tensile strain were grown by MBE using the doping technique of Ge by segregating impurities which was proposed by us earlier [JAP 118, 145701 (2015)]. Usage of this method allowed to achieve the electron concentration in Ge layers as high as Ne = 2×10^20 cm-3. It was shown that the elastic deformations introduced by Sb and determined by x-ray analysis are directly proportional to Ne, which makes it possible to use the x-ray analysis as an express method for determination of Ne in Ge:Sb structures. The grown structures demonstrate the plasmon wavelength in the range of 3.6-7 μm and can be used for detection in the 3-5 μm gas window. The value of the band gap narrowing effect for direct transitions at room temperature in Ge:Sb layers was found to be proportional not to Ne, as in the case of Ge: P layers [APL 102, 152106 (2013)], but to the bulk Sb concentration. Ge:Sb/Si(001) layers were used for formation of highly tensile strained microstructures which demonstrate noticeable increase of the RT luminescence signal.

Authors : Buse Unlu(1), Arman Ayan*(2), Samad Nadimi Bavil Oliaei(3), Selcuk Yerci(4), Cicek Boztug(5)
Affiliations : (1)TED University Department of Electrical and Electronics Engineering; (2)Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara, Turkey - Center for Solar Energy Research and Applications, Middle East Technical University, Ankara, Turkey; (3)Atilim University Department of Mechanical Engineering; (4)Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara, Turkey - Center for Solar Energy Research and Applications, Middle East Technical University, Ankara, Turkey - Department of Micro and Nanotechnology, Middle East Technical University, Ankara, Turkey; (5)TED University Department of Electrical and Electronics Engineering; *Presenting author

Resume : Strained germanium (s-Ge) is a promising material platform for the development of CMOS-compatible light sources for applications ranging from optical communication to bio-sensing. Even though its bulk counterpart is an indirect bandgap material, s-Ge emits light in a much more efficient manner through direct transitions. More importantly, s-Ge can provide optical gain for biaxial strain levels larger than 1.4% [1]. Motivated by these enhanced optical properties of s-Ge, in this work we have carried out finite element method (FEM) simulations to determine the amount of the strain in novel Ge microstructures on silicon. In these structures, strain is transferred from intrinsically-stressed silicon nitride stressor layer into suspended Ge microbridges. Strained Ge microbridges have been designed with strain levels above the threshold for obtaining optical gain in Ge. In the simulated structures, two ends of the microbridge are embedded in the stressor layer; therefore, by tuning the intrinsic stress of the stressor layer, the strain transferred to Ge can be modified without having to reduce the microbridge width down to the nanoscale. This is a great advantage, because micro-sized width of the Ge bridge would provide strong confinement of the mid-infrared lasing mode. Furthermore, the designed microstructures would possibly be fabricated utilizing liquid phase epitaxy, a low-cost CMOS-compatible fabrication method. 1. C. Boztug et al., Small 9, p 622-630 (2013)

Authors : Quang Minh Thai, Mathieu Bertrand, Nicolas Pauc, Rami Khazaka, Joris Aubin, Jérémie Chrétien, Alexei Chelnokov, Jean-Michel Hartmann, Vincent Reboud, Vincent Calvo
Affiliations : University Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA-Leti, Minatec, 17-rue des Martyrs, 38000 Grenoble, France; University Grenoble Alpes, CEA, INAC-Pheliqs, 38000 Grenoble, France

Resume : Germanium-Tin (GeSn) alloys have been studied recently as a potential candidate for Si-compatible light source due to the direct nature of their fundamental band gap at relatively high tin contents. So far, laser effects in GeSn were observed in Fabry-Pérot [1, 2] and micro-disk cavities [3, 4]. Photonic periodic structures offer another approach, besides mirror-based cavities, to achieve laser effect: Band edge mode, with its flat dispersion curve, has a quasi-zero group velocity, slowing down light propagation and enhancing light-matter interaction – a favorable condition for laser effect. In this study, we observe laser effect in GeSn 2D hexagonal photonic crystal with 16% of Sn, which we attribute (from comparison with simulation results) to band edge mode effect. The Ge0.84Sn0.16 active layer was grown on a GeSn step-graded buffer (itself on a Ge virtual substrate) to minimize defect density and preserve its crystalline quality. Based on the spectra and the Lin-Lout curve, we estimate the lasing threshold to be equal to 135 kW/cm2 at low temperature (15K), with an emitted wavelength of 2880 nm. Laser effect was observed only up to 60K, which could be the result of reduced overlap between the band edge mode position and the gain curve - the latter shifts towards higher wavelengths when temperature rises. Surface passivation and carrier confinement using SiGeSn alloys will be carried out in future studies to improve GeSn laser performance. [1] S. Wirths, R. Geiger, N. von den Driesch, G. Mussler, T. Stoica, S. Mantl, Z. Ikonic, M. Luysberg, S. Chiussi, J. M. Hartmann et al, Nature Photonics 9,88 (2015) [2] S. Al-Kabi, S. A. Ghetmiri, J. Margetis, T. Pham, Y. Zhou, W. Dou, B. Collier, R. Quinde, W. Du, A. Mosleh et al, Appl. Phys. Lett. 109, 171105 (2016) [3] D. Stange, S. Wirths, R. Geiger, C. Schulte-Braucks, B. Marzban, N. von den Driesch, G. Mussler, T. Zabel, T. Stoica, J-M Hartmann et al, ACS Photonics 3, 1279 (2016) [4] V. Reboud, A. Gassenq, N. Pauc, J. Aubin, L. Milord, Q.M. Thai, M. Bertrand, K. Guilloy, D. Rouchon, J. Rothman et al, Appl. Phys. Lett. 111, 092101 (2017)

Poster Session 1 : H. H. Radamson, A. Irrera, A. Ruzin, I. Berbezier
Authors : Ji Hun Choi, Sung Haeng Cho, Jong-Heon Yang, Jae-Eun Pi, Hee-Ok Kim, and Chi-Sun Hwang
Affiliations : Electronics and Telecommunications Research Institute (ETRI), Daejeon, 34129, Korea

Resume : The amorphous oxide thin-film transistors (TFTs) have received big attention as a good candidate of backplane for high resolution display application due to its great device performance. A combination of Indium, Zinc, Gallium, and Tin were often adopted for channel material since heavy-metal cations could show high electron mobility based on high degree of ns0 orbital overlap and conduction band dispersion. However, since the absolute value of the Gibbs free energy of these components are not that high, it could be easily oxidized in the oxide thin film to make oxygen vacancies, which deteriorated the device performances. In this regard, some researchers introduced aluminum for one of the channel material component for better device performance with high stability, but in-depth study on optimum condition of aluminum composition have not yet been investigated. In this study, the device performance of oxide TFTs with aluminum-doped indium-tin-zinc oxide (Al-InSnZnO) channel layer was examined. In particular, the effects of aluminum concentration in the channel layer on the device performance and material properties were investigated. A high field-effect mobility over 35 cm2/Vs, low sub-threshold slope of 0.12 V/dec and near-zero Von were achieved from optimally doped Al-InSnZnO condition. A little amount of aluminum in the channel improved the device performances. However, these enhancement were observed only when the amount of aluminum was lower than critical concentration.

Authors : M. J. Lo Faro1,2,3, A.A. Leonardi1,2,3,4, B. Fazio2, C. D’andrea2, P. Musumeci3, M. Galli5, C. Vasi2, F. Priolo1,3,6, A. Irrera2.
Affiliations : 1 MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania, Italy; 2 CNR-IPCF, Istituto per i Processi Chimico-Fisici, V.le F. Stagno D’Alcontres 37, 98158 Messina, Italy; 3 Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 4 INFN sezione di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 5 Dipartimento di Fisica, Università degli Studi di Pavia, via Bassi 6, 27100 Pavia, Italy 6 Scuola Superiore di Catania, Via Valdisavoia 9, 95123 Catania, Italy;

Resume : Semiconductor nanowires (NW) are of great impact as new materials for a broad range of applications. High-density arrays of ultra thin Si NWs with tunable aspect ratio were realized at low cost by metal-assisted chemical etching. By using Au layers with fractal arrangement, we engineered the synthesis of 2D random fractal arrays of vertically aligned Si NWs realized without any mask or lithography. By optimizing the size and spatial arrangement of NW fractals, we can tune the optical response of the system. Strong in-plane multiple scattering and efficient light trapping overall the visible range were observed due to the fractal structure(1), remarking the promising potential of Si NWs for photovoltaic and photonics. NWs achieved by this technique have the same structure and doping of the starting Si bulk, exhibiting a very bright room temperature PL tunable with NW size according to quantum confinement. Light emitting devices based on Si NWs showing an efficient room temperature EL emission at low voltage were reported. We demonstrate the first experimental observation of Raman coherent backscattering arising from the constructive interference of inelastically scattered Raman radiation in strongly diffusing Si NWs. The RCBS results are interpreted with a model of mixed Rayleigh-Raman random walks, exploiting the role of phase coherence in multiple scattering phenomena. 1. Light: Science & Applications 5 (4), e16062, 2016 2. Nature Photonics 11, 170, 2017

Authors : A. Daboussi 1, L. Mandhour1, S. Jaziri1,2
Affiliations : 1 Laboratoire de Physique de la matière Condensée, Faculté des Sciences de Tunis, Université de Tunis el Manar, Campus Universitaire Tunis, El Manar, 2092 Tunis, Tunisie 2 Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage, Jarzouna, 7021 Bizerte, Tunisie

Resume : We show that a stacking defect or a shift has a striking effect on carrier transport of bilayer graphene. Charge transport through a ballistic n–neutral–n junction of shifted bilayer graphene may result in minimal conductivity and shot noise anomalies which are found to be sensitive to the shift defect. Minimum conductivity and shot noise in shifted bilayer graphene exhibit an anisotropic beahavior as a function of the orientation of the electrodes. The minimum conductivity could be suppressed for somme specific value of twist defect while the shot noise takes the unit value.

Authors : Sangpil Park, Doo-Hyun Ko*
Affiliations : Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Republic of Korea

Resume : Copper Indium Gallium Selenide (CIGS) solar cell has been actively researched as clean energy technology with advantage of being flexible and thin film. However, conventional CIGS solar cells faced limitations as their photoactive layer cannot sufficiently absorb light due to reflection of incident light. To overcome these drawbacks, we fabricated PDMS film with randomly formed patterns, so-called “Optical haze film” through a combination of simple Aluminum hydrolysis with imprinting method. Optical haze film increase absorption of solar cell by extending light path of incident light. Also, Random nanostructures formed on film reduce reflection of incident light by gradually changing refractive index of interface surface. By simply attaching the haze film onto CIGS solar cell, we improve photo-conversion efficiency of CIGS solar cell by 8.8% from 9.78 to 10.64%.

Authors : Wenjuan XIONG; Henry H Radamson;
Affiliations : Institute of microelectronic chinese academy of science

Resume : This work presents a novel process to form SiNx membranes which offer excellent properties compared to conventional LPCVD furnace process. This SiNx films are fabricated in SiNgen apparatus which is a single wafer chamber equipment. The films show low stress, good mechanical properties, but also eradicate the issues of particulate contamination and realize maintenance simply. Through adjusting the source gas flow rates in Singen chamber and changing subsequent annealing temperature and time, low stress (40Mpa) SiNx film have been finally made out when annealing temperature rises up to 1150℃. It is because more of Si nano-crystalline informed with the increasing of annealing temperature, according to the FTIR characterization. Its mechanical properties, Young's modulus and hardness, were 210Gpa and 20Gpa respectively. Both of them had a little difference with conventional low stress SiNx.

Authors : Gaehang Lee
Affiliations : Korea Basic Science Institute (KBSI), Daejeon, , Republic of Korea

Resume : Gold nanoparticles (AuNPs) have been investigated widely because of their unique catalytic, optical, and electrical properties. In particular, among various shape, well-defined spherical AuNPs could provide simplicity and precision for optical engineering research (i.e., Fano-like resonance, extinction coefficient, and scattering). Recently, we have established a synthetic route for obtaining monodisperse, ultra-smooth, and highly spherical AuNPs larger than 30 nm by advancing the experimental conditions of chemically etching faceted Au octahedron; unprecedented quality of these ideally spherical AuNPs with a relatively large size have been confirmed by our spectral measurements. In extension research, we have systematically studied the UV-Vis absorbance behavior and extinction coefficients for our ideally spherical. Also, the super-spherical AuNPs allowed to deterministic and reliable assembly in a short time as metamolecules by AFM-enabled manipulation, in comparison with polygonal shaped AuNPs.

Authors : Margoth Lorena Torres1, Raj Kumar Patra2, Ilona Skorupa3 Heidemarie Schmidth2, Oliver G Schmidt2, Maria Elena Gomez1
Affiliations : 1Thin film group, Department of Physics, Universidad del Valle, Calle 13 # 100-00 Cali, Colombia. 2Material Systems for Nanoelectronics, 2Technische Universität Chemnitz, 09126 Chemnitz, Germany 3 Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany

Resume : The purpose of this work was to analyze the carrier transport properties of n-p Co(Mn)-doped ZnO/YMnO3 heterojunctions diodes (NpHJDs) by capacitance-voltage using the Poisson's equation and current-voltage measurements. We use type of atoms, atom percent and number of pulses by PLD as variables. The Co(Mn)concentration was systematically change at un-dopped, 0.1, 2.0 and 5.0 atom percent. Additionally samples were grown at 1500 and 2500 pulses by pulsed laser deposition technique where we varied the frequency of the laser pulses for the doped ZnO films maintaining constant all the other growth parameters. The donor concentration, Nd, build-in voltage, Vd, for all NpHJDs, were calculated assuming the acceptor concentration, Na = 1020 cm-3. Results indicate a dependence of Nd, Vd and widths of the depletion region with at.% Co, at.% Mn, and growth parameter frequency of laser. The Nd showed a dependence respect to number of pulses, and at increased doping concentration for Co(Mn)-doped samples presented a minimum. Lower values than 1019 cm-3 for Nd had found ferromagnetism properties1 these could suggest that this samples to will be candidate for ferromagnetism properties at room temperatures also. From I-V curves of NpHJDs were modelling by multistep tunnel and we found the forward current density respect to temperature and voltage dependence of the samples and their conduction modes.

Authors : Dae-Young Jeon, Dong Su Lee, Seoung-Ki Lee, Min Park, So Jeong Park, Gyu-Tae Kim
Affiliations : Korea Institute of Science and Technology (KIST) and Korea University

Resume : Partially depleted (PD) MoS2 transistors were fabricated and discussed about their operation mechanism with considering maximum full-depletion width (Dmax) and impact of series resistance (Rsd). PD-MoS2 transistors had a constant channel due to undepleted neutral regime even at very low Vg, as well as gate-controllable channel within Dmax. The gate-controllable current (Id_gcc) was simply separated from as-measured drain current. Then, series resistance was extracted by using Y-function method and its impact in Id_gcc was eliminated. In addition, an intrinsic bulk neutral mobility in PD-MoS2 transistors was extracted from simply separated gate-controllable drain current with depletion approximation. This work provides critical information for a better understanding physical operation of PD-MoS2 transistors and further optimization of their performance for More Moore technologies with diverse applications.

Authors : Yoonjoong Kim, and Sangsig Kim*(corresponding author)
Affiliations : Department of Electrical Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea

Resume : Over the past few decades, the scaling of conventional silicon-based memories has been remarkably improved with the Moore’s law. But, recently, the scaling of these memories has reached its theoretical and practical limits. It is crucial to exploit new types of devices and materials compatible with conventional silicon technology. Among several emerging memories, feedback field-effect transistors (FETs) are one of promising candidates for next-generation memory devices with low supply voltages, clear hysteresis loops and long retention times. Furthermore, with laterally isolated floating nodes in the form of nanocrystal, feedback FETs can expand their application to non-volatile memory. Hence, we demonstrate non-volatile memory characteristics of silicon nanowire (SiNW) feedback FETs with discrete trap storage nodes of Pt nanocrystals. A feedback FET was fabricated with the combination of the SiNW (diameter ~100 nm), a high-k (Al2O3 ~20 nm) gate dielectric, a Pt nanocrystal floating gate layer and aluminum (Al ~ 100nm) source/drain/gate metal electrodes. This device exhibits a clear counter-clockwise hysteresis loop after a programming operation of 9 V for 1 s. It also shows the on/off current ratio of ~ 10^6, the long retention time of up to ~ 10^4 s, and the program/erase endurance up to 1000 cycles. This study demonstrates the promising potentiality of our feedback FET for the next-generation non-volatile memory electronics.

Authors : Doohyeok Lim, Yoonjoong Kim, and Sangsig Kim*(corresponding author)
Affiliations : Korea University

Resume : In this work, we demonstrate the steep slope subthreshold characteristics of silicon nanowire (SiNW) feedback field-effect transistors (FBFETs) with a dual-top-gate geometry. SiNWs were derived from a bulk-Si wafer including ion implantation and crystallographic wet etching process, and the SiNWs were then transferred onto a plastic substrate. Each of the SiNWs had a diameter of 150 nm. BF2+ and As+ ions were implanted for the formation of p+ and n+ regions in the SiNWs, respectively. The channels of the transistors consisted of SiNWs with p+-i-n+ diode structures, and the i-regions of the channels were covered by Al2O3 high-κ dielectric layers and dual-top-gate electrodes. Our FBFET shows a sub-60mV/dec subthreshold swing at room temperature generated by the positive feedback loop. However, the positive feedback loop generates the hysteresis characteristics, which is undesirable in currently used switching devices. The hysteresis window can be controlled by the fixed gate bias voltages. The fixed gate bias voltage plays an important role in the positive feedback loop by modulating the height of potential barriers. Therefore, our dual-gate FBFET shows the steep subthreshold slope with the negligible hysteresis characteristics by controlling the positive feedback loop.

Authors : Paulo Lourenço, Alessandro Fantoni, Manuela Vieira
Affiliations : ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Rua Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, Portugal; Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Departamento de Engenharia Eletrotécnica, Campus da Caparica, 2829-516 Caparica, Portugal; CTS-UNINOVA, Departamento de Engenharia Eletrotécnica, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal

Resume : Sensors based on Surface Plasmon Resonance (SPR) phenomenon are highly sensitive to variations of the surrounding environment refractive index. In this work, it is considered a cost-effective approach through the selection of aluminum as the active plasmonic material and hydrogenated amorphous silicon as the material for the waveguide, instead of its crystalline counterpart. This surface plasmon resonance device relies on Fano resonance to improve its response to refractive index deviations of the surrounding environment. Fano resonance is highly sensitive to slight changes of the medium, hence the reason we incorporated this interference phenomenon in the proposed device. We report the results obtained when conducting simulations based on Finite-Difference Time Domain algorithm based simulations on this metal-dielectric-metal structure. Sensitivity, detection accuracy and resolution is evaluated together with its ability to detect refractive index variations of the surrounding environment at the near infrared operating wavelengths. This structure also shows the capability of subwavelength transmission due to the strong light confinement produced by the metal-dielectric-metal (MDM) structure.

Authors : PengZhang, BoTang, BinLi ,ZhihuaLi, JinzhongYu
Affiliations : Institute of Microelectronics of Chinese Academy of Sciences

Resume : Silicon photonics has emerged as an attractive platform for data communication in fiber optics and intra-chip communications. IMECAS is developing a silicon photonics process platform based on existing 22nm CMOS platform, so the wafer-level test solution presented in this paper plays an extremely important role in process validation and optimization. We design a low cost test system which enables optical and electro-optical testing of passive and active silicon photonics components and circuits, including waveguides, splitter, grating couplers, photodetectors, modulators etc. It is compatible with 200mm wafer-level testing and Die-level testing. Meanwhile, it has two coupling ways: edge coupling and grating coupling.

Authors : Shihai Gu1, Guilei Wang1,2, Jun Luo1,2, Tao Yang2, Husan Cui2, Junjie Li2, zhenzhen Kong1,Junfeng Li2, Wenwu Wang1,2, Tianchun Ye1,2, Chao Zhao1,2, Henry H Radamson1,2,3
Affiliations : 1 Key laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People’s Republic of China; 2 University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China; 3 KTH Royal Institute of Technology, Brinellv. 8, 10044 Stockholm, Sweden;

Resume : Epitaxial growth of III–V high mobility channel materials on patterned Silicon substrate is important alternate option for future (opto-) electronic devices, such as 3D FinFETs [1]. Defect control and reduction during growth is still a key research topic nowadays. It has been demonstrated that growth on a pre-patterned substrate can result in a high-quality material with a Shallow-Trench-Isolation (STI) pattern, the lateral dislocation induced by lattice mismatch can be effectively limited near the interface. Therefore, the top region contains less defects and can be used for device fabrication [2]. At the same time, the transverse dislocation induced by two adjacent islands merging during growth will be a limitation for further application. In this study, SiO2 STI pattern was applied on 200 mm on-axis Si (001) substrates to realize 70 nm deep trenches with 40 nm widths [3]. The average active area reserved to the III-V layers deposition was kept at 1% of the total Si wafer surface. The trenches are aligned along a <010> direction, silicon recess engineering obtained by wet etching using tetramethylammonium hydroxide (TMAH) will stabilize the {111} planes of Si in the bottom of the trenches, this allowed to initiate the III-V materials growth on V-groove with a rough surface, and this rough surface provided some growth steps for initial homogeneous nucleation. The III-V heteroepitaxy has been performed in a 200 mm AIXTRON CRIUS MOVPE reactor. Epitaxy of GaAs/InP on Si is a fundamental research on other III–V materials, the Group-III and V organometallic precursors used are triethylgallium(TEGa) and tertiarybutylarsine (TBAs) in this research. Due to the low thermal decomposition temperature of these precursors, the applied seed layer growth temperature can be very low. The epi-layers were characterized by high-resolution x-ray diffraction (HRXRD), rocking curves were performed at (004) and (224) reflection. The cross-section of the GaAs-fins on the Si were performed by high-resolution scanning electron microscopy (HRSEM) and transmission electron microscopy (HRTEM) to confirm the layer thickness and epi-quality. The main goals of this study were to grow high quality InP in the trenches for FinFETs and later to increase the trench density to cover the entire the wafer with InP when the lateral growth continues from the trenches. In both cases, the defect density could be tuned by optimizing the growth parameters, the aspect ratio and the density of the trenches. Acknowledgement This work was financially supported by “National S&T Major Project 02”, the opening project of Silicon Based High Mobility Materials and Devices Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences (Project No. 2011ZX02708-005), which are hereby acknowledged. References [1] Radamson, H. H., Zhang, Y., He, X., Cui, H., Li, J., Xiang, J., ... & Wang, G. (2017). The Challenges of Advanced CMOS Process from 2D to 3D. Applied Sciences, 7(10), 1047. [2] C.Merckling, N.Waldron, S.Jiang, W.Guo, P.Ryan, N.Collaert M.Caymax ,et al. Selective-Area Metal Organic Vapor-Phase Epitaxy of InGaAs/InP Heterostrucures On Si For Advanced CMOS Devices, ECS Transactions, 61 (2) 107-112 (2014). [3] Guilei Wang, Jun Luo ,Changliang Qin, Hushan Cui, Jiniao Liu, Kunpeng Jia, Junjie Li, Tao Yang, Junfeng Li, Huaxiang Yin, Chao Zhao, Tianchun Ye, Ping Yang, G. Jayakumar and Henry H. Radamson.(2016). Integration of Selective Epitaxial Growth of SiGe/Ge layers in 14nm Node FinFETs, ECS Transactions, 75 (8) 273-279 (2016)

Authors : Wai Kin Lai, Shu Ping Lau
Affiliations : Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR

Resume : Phosphorus exhibit three common allotropes, which include white, red and black phosphorus. In addition, phosphorus also has another relatively rare allotrope called violet phosphorus (VP). VP is a monoclinic with double tubes layered structure. It has been predicted theoretically that monolayer VP has a high anisotropic hole mobility (3000 - 7000 cm2/Vs) and a wide direct band gap of 2.5 eV. In this work, VP crystals were grown by chemical vapour transport (CVT) method using red phosphorus, tin powder and I2 as precursors. The VP crystals can be exfoliated by mechanical and ultrasonic methods. The VP flakes exhibit strong thickness dependence photoluminescence (PL). The PL emission of the VP flakes can be tuned from 680 to 600 nm as the VP thickness decreases from 100 nm to 10 nm respectively.

Authors : So Jeong Park, Kook Jin Lee, Il-Hoo Park, Jong Mok Shin, Jun Hee Choi, Hyeon-Jeong Kim, Hyebin Lee, Hyeon-pil Joo, Dae-Young Jeon, Gyu-Tae Kim
Affiliations : School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea;Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Joellabuk-do 55324, Korea;School of Electrical Engineering, Korea University, Seoul 136-701, Korea

Resume : Ionic liquid-gated field effect transistors(FETs) utilize an electric double layer having potentially large capacitance as a gate dielectric. With the large dielectric capacitance, the device can induce high density of carriers, enabling high on-current and low operation voltage. Among electrolyte dielectrics forming electric double layers at the electrolyte-solid interface, particularly, ionic liquid has advantages such as wide electrochemical window, high thermal and chemical stability, non-volatility and nontoxicity. To understand the operation of ionic liquid-gated transistors, the electrical characterization of the transistor is essential and the electrical measurement tool is required, which will be critical for mobile application such as gas detectors. In the present work, ionic liquid-gated FETs based on 2-dimensional nanosheets with atomically thin electric double layer were fabricated and measured with our mobile measurement set-up. Designed measurement set-up using microcontroller provides cheaper and portable measurement solution even with wireless communication. With low noise preamplifiers, low current (<1nA) measurements were successfully demonstrated with the function of machine learning algorithm, which can be used in the mobile devices.

Authors : MariaAnna Messina1, Antonio Leonardi2, Federica Raudino1, Sabrina Conoci3, Salvatore Petralia3
Affiliations : 1 Azienda Ospedaliero Universitaria Policlinico Vittorio Emanuele, Via S. Sofia 78 2Dep. of Phys. And Astron. University of Catania, Via S. Sofia 64 Catania, Italy 3STMicroelectronics, Stradale Primosole, 50 – 95121 Catania, Italy

Resume : Phenylketonuria (PKU) is a rare inherited metabolic disorder mainly caused by mutations in the gene Phenylalanine Hydroxylase which results in low levels of the corresponding enzyme. This involves the buildup of dietary phenylalanine to potentially toxic levels. Indeed high levels of Phe damage the brain and cause severe and irreparable intellectual disability. The main treatment for this disorder is based on a dietary restriction of Phe. Therefore the control of Phe level in blood or urine is the primary marker for guiding available treatments. In this context we developed a novel integrated silicon-paper based sensor for the fast measurement of Phenylalanine level on urine, useful for the monitoring of dietary therapy efficiency for patients affected by PKU disorder. The system integrates a sensing strategy based on the fast deamination reaction of Phenylalanine catalyzed by Phenylalanine Ammonia Lyase (PAL) enzyme to produce trans-cinnamic acid and ammonia. The ammonia produced increase the pH value of sample. The reaction is easily monitored through a pH indicator which induces a color change of sample solution. In this scenario the color solution in correlated to the amount of Phe present on urine sample. The correlation between the Phe amounts with the color of solution, was performed by a properly chromatic-scale created using standard solutions of Phe in the range from 20 to 3000 μM. The device is composed by a silicon parts integrating temperature sensors and heaters for temperature control (accuracy of about 0.1 °C) and a plastic ring to form the microreactor featured by a total volume of 200 µl. The paper substrate for enzyme immobilization was glued upon the silicon substrate. The device is thermally managed by a customized equipment and software. The PAL enzyme and reagents were properly immobilized at paper surface substrate and the reaction performed at temperature of 35°C and pH 8.3. In order to evaluate the performance of assay with real samples a rapid test format the reagent on board device The method was validate by comparison with the standard MS-MS technique. The proposed system permits the monitoring of Phe in a dynaminc range concentration of 20-3000 µM, with a Limit of Detection of about 20 µM.

Authors : Hyunjeong Kim,Wungyeon Kim,So Jeong Park,Hyebin Lee,Hyeon-pil Joo,Gyu-Tae Kim
Affiliations : School of Electrical Engineering, Korea University, Seoul 136-701, Korea

Resume : Two-dimensional (2D) materials were extensively examined as promising materials for nanoelectronics. Layered transition-metal dichalcogenides (TMDs), such as MoS2. However, reliability of TMDs materials for future electronics should be further investigated since TMDs are facing serious reliability issues. We study hysteresis of top-gated MoS2 FETs with various gate length. The gate electric field depends on the ratio of the length of the channel to the gate, which also affects hysteresis behavior. The effects of both interface trap and mobile charge together induce intersection in transfer characteristics regardless of gate length. However, in device with the thick gate length, interface trap is found to be dominant leading to clockwise hysteresis whereas in the one with the thin gate length, mobile charge is dominant leading to counter- clockwise hysteresis. In addition, we demonstrate that hysteresis behavior with sweep rate and temperature depends on gate length. Our study is helpful to understand hysteresis of TMDs devices.

Authors : J. L. Frieiro,1,2 O. Blázquez,1,2 J. López-Vidrier,3 S. Hernandez,1,2 B. Garrido1,2
Affiliations : 1MIND, Department of Engineering: Electronics, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); 2Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Av. Joan XXIII S/N, E-08028 Barcelona (Spain); 3Laboratory for Nanotechnology, Dept. of Microsystems Engineering (IMTEK), University of Freiburg, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, D–79110 Freiburg (Germany)

Resume : Recently, memristive materials have attracted great attention due to their ability of resistance switching (between high and low resistance states) via voltage application. Thus, they can be implemented in either optically-readable or electronic memories. In particular, Si-based oxides have demonstrated to be an excellent candidate for being implemented as active layer in resistive switching devices (memristors). Nevertheless, the out-diffusion of oxygen ions from the active layer through the electrodes states a drawback at large number of switches. Adding materials that prevent this out-diffusion can improve the performance, and thus the endurance, of the devices. In this work, the resistive switching properties of Al/SiO2 nanomultilayers (NML), fabricated by electron beam evaporation, have been studied. We observed that devices present memristive properties, but with very limited switching cycles, presumably due to the large out-diffusion of oxygen from the Al/SiO2 bilayer (degradation of the active layer). A new set of devices was fabricated introducing nanolayers of Tb within the Al/SiO2 stack. These devices also exhibit resistive switching properties with a durability enhancement, as well as a more pronounced difference between the high and the low resistance states. This result suggests that the Tb ions are limiting the out-diffusion of oxygen from the Al/SiO2 stack. Finally, the charge transport mechanisms have been studied and compared for the two set of devices.

Authors : S.Ya. Khmel, E.A. Baranov, A.O. Zamchiy, Yu.G. Shukhov, S.V. Starinskiy, A.V. Bulgakov
Affiliations : Kutateladze Institute of Thermophysics, Novosibirsk, Russia

Resume : The phenomenon of localized surface plasmon resonance (SPR) of metallic nanoparticles, in particular gold nanoparticles, is used for the fabrication of sensors for biological and chemical applications. One way to increase the sensitivity of SPR sensors is to increase the density of metal nanoparticles by using an array of nanowires instead of a flat substrate. In this paper we propose to use arrays of bundles (microropes) of nanowires of silicon oxide (SiOx). Arrays of oriented microropes of SiOx nanowires were synthesized by gas-jet electron beam plasma chemical vapor deposition method using a monosilane-argon-hydrogen mixture and oxygen on a tin catalyst with the substrate temperature 335 С. The arrays of microropes were decorated by Au nanoparticles with help of pulsed laser ablation. We used the second harmonic of a nanosecond Nd:YAG laser (wavelength 532 nm, pulse length 7 ns) with an energy density of 8.4 J/cm2. The morphology of the samples was observed with a JEOL JSM-6700F scanning electron microscope. Optical response of the samples was performed in a range of 300–1100 nm wavelengths using a DFS-452s spectrophotometer equipped with a photodiode array. The arrays of microropes of SiOx nanowires were uniformly coated with Au nanoparticles. An intense SPR peak was observed in the extinction spectra for samples with different nanoparticle average size, microrope lenght. This study was financially supported by the Russian Science Foundation, project # 16-19-10506.

Authors : Adelberg A., Ponnuvelu D., Marunko S., Ruzin A.
Affiliations : Department of Physical Electronics, School of Electrical Engineering, Tel Aviv University, Israel

Resume : Silicon-germanium with diffused lithium atoms is considered as X-ray detector. Compared to Si(Li) it has potential advantages. The main one is a much higher atomic number that provides a significant increase in absorption efficiency. In this study Czochralski grown silicon-germanium single crystals were used. It is known that bulk SiGe is difficult to grow because of the segregation of germanium. Crystals grown by the Float Zone technique are only available in small sizes. The Czochralski method allows the growth of large crystals, but with a lower resistivity. This problem is solved in the study by lithium atoms diffusion and drift. The processes of chemical and mechanical treatment of crystals, diffusion and drift processes were investigated to provide detectors with optimal current, capacitive and noise characteristics. The dependence of the lithium diffusion coefficient on the germanium concentration is shown. The value of the surface concentration of lithium in silicon-germanium is compared with values reported for pure silicon crystals.

Authors : Kamalakannan Ranganathan, Pavel Baykov, Tamir Amrani, Anastasia Adelberg, Ilan Goldfarb and Arie Ruzin
Affiliations : Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv, Israel

Resume : Nonvolatile memory is expected to be the next leap in computer technology. There is a stiff competition among leading research groups to develop alternatives to DRAM and NAND FLASH memory technology. A strong contender is the memristor based nonvolatile memory1. The resistive transitions of a memristors were potential for multi-level memories2. Though, binary devices were reported widely than multi-level devices due to lack of control on non-linear resistive regime of switching. The aims of this research were to address fundamental scientific issues in the development of nonvolatile multi-level memristor. Hafnium oxide based memristor were fabricated on Si/SiO2 substrate. The layers of TiO2/Pt/HfOx/Ag were coated on Si/SiO2 substrate. The results show two logic states of the memristors which reflecting its ability to switch between two distinct resistance levels (on/off states). These switching were presumed by creation and destruction of conductive channels, which were verified by different electrical conditions. The multi-level set state was tested with various series resistance (0 Ω to 500 kΩ) and compliance. The paper discusses the volatility of stored memory in the memristor while switching with low current and provide the insight for the optimum requirement of power and possibility of multi-level storage.

Authors : Guilei Wang1,2*, Jun Luo1,2, Jinbaio Liu1,2, Tao Yang1, Hong Yang1,2, Zhenzhen Kong1, Huaxiang Yin1,2, Huilong Zhu1, Junfeng Li1, WenWu Wang1,2, Chao Zhao1,2 and Tianchun Ye1,2
Affiliations : 1 Key laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, P. R. China 2 University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China

Resume : As the Complementary Metal-Oxide-Semiconductor (CMOS) continuous scaling down to sub-20 nm nodes, strain engineering is applied as a key technique to boost device performance. There are many useful methods to induce the strain to the device channel. One of these methods, metal-gate stress technology (MGS) is attracting tremendous attention because of its easy integration with the current high-k & metal gate (HKMG)-last integration scheme and its effectiveness in inducing strain to the channel [1]. As known, the aspect ratio (AR) of dummy gate trench became larger as scaling down to sub-20 nm nodes, filling the gate trench without voids or seams by traditional Al metal faced overwhelming challenges. Hence, because of a good step coverage and conformity W metal using atomic layer deposition (ALD) emerges as a competitive candidate in filling the dummy gate trench [2] In this study, ALD W Using SiH4 and B2H6 precursors as filling metal in pMOSFETs were investigated. It was found that, compared to devices filled by ALD W using B2H6, devices filled by ALD W using SiH4 show higher drive capability and better control of short channel effects. The on-current, DIBL and SS for the latter are 703 µA/µm (Vds=Vgs=-1.0 V), 98 mV/V and 88 mV/dec, respectively. The superior device performance for devices filled by ALD W using SiH4 results from large compressive stress applied to the channel. Thanks to the large stress as well as excellent trench filling capability of ALD W using SiH4, this

Authors : Guilei Wang1,2*, Jun Luo1,2, Jinbaio Liu1,2, Tao Yang1, Hong Yang1,2, Zhenzhen Kong1, Shihai Gu1, Huaxiang Yin1,2, Huilong Zhu1, Junfeng Li1, WenWu Wang1,2, Chao Zhao1,2, and Tianchun Ye1,2
Affiliations : 1 Key laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, P. R. China 2 University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China

Resume : As CMOS technology downscaled into 22 nm and beyond, a transition planar (2D) to three-dimension (3D) transistors happened and a revolutionary silicon FinFET structure was introduced to the semiconductor industry for mass production [1,2]. However, the FinFET structure design has increased the complexity of the processing and presented a lot of technological challenges in processing fins with regular shapes and controlling sidewall edges. To make high strain amount in the channel area, SiGe layer was Selective epitaxial growth (SEG) in source/drain areas as stressor materials [3]. The epitaxial quality of SiGe is very sensitive to the surface quality of Si-fins. Hence, the hydrogen annealing in pre-baking process of Si-fins is an important step prior to the epitaxy to remove any native oxide or residual impurities (C) on the Si-fins’ surface. In this study, the impacts of Si-Fins structural modification and optimization by hydrogen annealing was investigated. It is found that Si-fin is a delicate part of a FinFET structure where its shape can be modified and controlled by a hydrogen annealing treatment inside the epitaxial chamber prior to the epitaxy growth. The studies have demonstrated that hydrogen annealing temperature and chamber pressure are the key parameters to modify shape of Si structure. It was also found that hydrogen annealing at lower temperature as 780-800 ゜C is necessary to remove native oxide but to preserve the shape of Si fins which is essential for high-quality SiGe SEG. In addition, a little Si Fin loss at high hydrogen annealing temperature is attributed to HCl etching because of residual Cl atoms inside chamber. As hydrogen annealing chamber pressure is lower, the morphology changes a lot and this is caused by the migration of Si atoms. Cross-section images were provided by high-resolution scanning electron microscopy (HRSEM) and transmission electron microscopy (HRTEM) to monitor the morphology change of Si structure and measure the layer thickness, epi-quality.

Authors : Michele Casiello,1 Alessio Leonardi,3,4 Rosaria Anna Picca,1 Caterina Fusco,2 Lucia D’Accolti,1,2 Antonio Maria Josè Lo Faro,3 Sebastiano Trusso,3 Pietro Cotugno,1 Maria Chiara Sportelli,1 Nicola Cioffi,1, Angelo Nacci,1,2
Affiliations : 1Dipartimento di Chimica, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona, 4 – 70126 Bari, Italy 2CNR-ICCOM, UOS Bari, Via E. Orabona, 4, 70126 Bari, Italy 3IPCF-CNR, viale F. Stagno d’Alcontres 37, Faro Superiore, 98158 Messina, Italy 4Dipartimento di Fisica ed Astronomia, Università di Catania and INFN Sezione di Catania, Via Santa Sofia, 68, 95125 Catania, Italy

Resume : Metal-based nanocatalysts are increasingly proposed as active materials for pollutant reduction, such as aromatic nitrocompounds [1]. Typically, such nanosystems are prepared accordingly to chemical routes implying the use of stabilizing agents, which in turn may affect negatively their catalytic performance. Here, we propose an innovative hybrid catalyst based on metal nanoparticles (MeNPs) supported onto well-ordered arrays of silicon nanowires (SiNWs). In particular, pulsed laser deposition of “unstabilized” copper (or gold) NPs was carried out on SiNW arrays achieving the homogenous and efficient coverage of such substrates, as demonstrated by scanning electron microscopy. The excellent catalytic activity, attested by the very high turnover number values, is due both to the uniform coverage along the nanowire length and the absence of capping agents surrounding MeNPs [2]. The high recyclability was ascribed to the strong covalent interaction at the metal-Si interface by virtue of silicide formation. [1] H. Hu, et al, J. Mater. Chem. A 3 (2015) 11157 [2] M. Casiello, et al., Nanomaterials 8 (2018) 78, doi:10.3390/nano8020078.

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Session 3: Nanoelectronics : J. Luo
Authors : Yakov Roizin
Affiliations : TowerJazz, Israel

Resume : Both deeply scaled down digital microcircuits and gaining an increased importance analog semiconductor systems employ materials different from those in the traditional CMOS electronics. For example, in the emerging IoT and smart automotive applications, sensors receiving analog signals from the physical world and ultra-low power neuromorphic processors include alternative materials. While in the state of the art digital technologies, advanced oxides and compound semiconductors on silicon platforms have been considered, modern analog electronics requires a much wider spectrum of alternative materials. A more complicated device physics of analog devices is superimposed with the need to characterize these materials and their performance after integrating with CMOS. Integration of alternative materials has a lot of challenges for a semiconductor foundry when running diverse analog products and CMOS devices in the same clean room. Segregated areas and strict and complicated contamination protocols are necessary. Additional equipment for characterization, sort and qualification is required. We illustrate how these challenges are addressed on the examples of technologies recently developed and integrated into the CMOS process flows in TowerJazz fabs . The examples include nanosensors based on magnetic tunnel junctions, silicon quasi nanowires and GaN on silicon, memories and 3D capacitors with high-k dielectrics in the back end, RF switches with phase change materials, germanium photodetectors and special nitrides for silicon photonics.

Authors : Po-Yuan Chiu1*, Chia-You Liu2, Yen Chuang2, Charles Thomas Harris3, Tzu-Ming Lu3, and Jiun-Yun Li1,2,4
Affiliations : 1 Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan 2 Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan 3 Sandia National Laboratories, Albuquerque, New Mexico 87185, USA 4 National Nano Device Laboratories, Hsinchu 30078, Taiwan *E-mail:

Resume : Ge is one of the candidates to replace Si as a channel material in the next-generation CMOS technology due to the high hole mobility. Furthermore, it is also a promising material for semiconductor spintronics due to its strong spin-orbit interaction (SOI). Until now, the SOI in Ge has been observed in the modulation-doped Ge/GeSi heterostructures, where the hole density can be modulated by applying different voltages on gate metal or by varying the remote doping concentration and the distance between the two-dimensional hole gas (2DHG) and the remote doping layer. In thlis work, we introduce a new ex-situ doping method that can achieve different doping densities in a single undoped Ge/GeSi heterostructure. By implanting Ga with different fluences into the GeSi spacer layer to form a modulation-doped layer, Ge 2DHGs can formed. The carrier density measured at 1.5 K increases linearly with the ion fluence and the carrier activation rate of implanted ions is ~ 40%. Thus, by calibrating the carrier density dependence on the ion fluence, one can modulate the 2DHG density easily. Clear quantum Hall plateau was observed, indicating well sample quality. Acknowledgements This work at NTU has been supported by the Ministry of Science and Technology (106-2112-M-002-009-). This work at Sandia National Laboratories has been supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, US Department of Energy (DOE). This work was performed, in part, at the Center for Integrated Nanotechnologies, a US DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under Contract No.DE-NA-0003525.

Authors : Dor Gabay1, Xueang Wang2, Vitaly Lomakin2, Amir Boag1, Manish Jain3, and Amir Natan1,4
Affiliations : 1Department of Physical Electronics, Tel-Aviv University, Tel-Aviv, Israel 69978 2Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA 3Department of Physics, Indian Institute of Science, Bangalore 560 012, India 4The Sackler center for computational molecular and materials science, Tel-Aviv University, Tel-Aviv, Israel 69978

Resume : We analyze the size dependence of silicon quantum dots (QDs) electronic band gap. An efficient scheme for the calculation of hybrid and screened hybrid density functionals (DFT) is used to calculate the electronic properties of silicon QDs of size up to ∼800 atoms and volume of up to ∼20nm3. Those calculations are compared with other theoretical estimations and with experimental measurements. We show that the HSE functional yields a band gap that is slightly above the measured optical gap. Finally, we also calculate the ionization potentials of such QDs and show that different approximation methods give similar values.

Authors : Maxime Chambonneau 1, Sarra Souiki-Figuigui 2, Philippe Chiquet 2, Vincenzo Della Marca 2, Jérémy Postel-Pellerin 2, Pierre Canet 2, Jean-Michel Portal 2, David Grojo 1
Affiliations : 1 Aix-Marseille University, CNRS, LP3 UMR 7341, Marseille, France 2 Aix-Marseille University, CNRS, IM2NP UMR 7334, Marseille, France

Resume : The irradiation of bulk silicon with femtosecond infrared pulses is known to result in the production of underdense transient microplasmas. Nonlinear effects associated with the laser beam propagation limits the energy deposition and prevent the material from any permanent modification. Taken together, these two ultrafast laser-semiconductor interaction properties are particularly interesting for controlling and probing silicon-based microelectronic devices by fast, contactless, and noninvasive techniques. In this study, we demonstrate the possibility to generate and transport free-electrons across single isolated Flash memories – and to consequently modify their memory state – with femtosecond laser backside irradiations at 1300 nm wavelength. For both the initially erased and programmed configurations of the device, an identical final state is found after repeated irradiations. This state is interpreted as the one for which the band diagram is flat, as supported by a specifically developed model accounting for two-photon ionization of silicon, quantum tunneling of free-electrons through a 10 nm oxide layer, and recombination of the carriers. Additional experiments performed by varying the laser energy and also by applying a bias on the control gate corroborate this theoretical scenario. The whole set of results holds a lot of promises for fast device analyses (e.g., reliability, defectivity) and for the growing field of ultrafast microelectronics.

Authors : Po-Yuan Chiu1*, Chia-You Liu2, Yen Chuang2, Charles Thomas Harris3, Tzu-Ming Lu3, and Jiun-Yun Li1,2,4
Affiliations : 1 Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan 2 Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan 3 Sandia National Laboratories, Albuquerque, New Mexico 87185, USA 4 National Nano Device Laboratories, Hsinchu 30078, Taiwan *E-mail:

Resume : Germanium–tin is probably the most important puzzle for Si photonics due to its direct bandgap nature as the Sn fraction is higher than 8~11% [1]. On the other hand, due to the presence of Sn in the GeSn alloys, strong spin-orbit interaction is expected. For the designs of GeSn-based optoelectronic and spintronic devices, the information of the effective mass is crucial. In this abstract, we present the high-quality modulation-doped Ge0.92Sn0.08/Ge heterostructures grown by reduced pressure chemical vapor deposition. The hole concentration is 3.3 x 10^11 cm^-2 and the mobility is 24,0000 cm^2/V-s at 4 K. Magnetoresistance measurements were also performed at 1.14 ~ 10 K. Well-resolved Shubnikov-de Hass oscillations were observed with clear quantum Hall plateaus. The effective hole mass was extracted to be 0.12 m0. Acknowledgements This work at NTU has been supported by the Ministry of Science and Technology (106-2112-M-002-009-). This work at Sandia National Laboratories has been supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, US Department of Energy (DOE). This work was performed, in part, at the Center for Integrated Nanotechnologies, a US DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under Contract No.DE-NA-0003525. Reference [1] Wirths, S. et al. Lasing in direct-bandgap GeSn alloy grown on Si. Nature Photon. 9, 88–92 (2015).

Session 4: Nanostructures luminescence : A. Ruzin
Authors : M. Sistani, P. Staudinger, F. M. Brunbauer, S. Krall, E. Bertagnolli, A. Lugstein
Affiliations : Institute of Solid State Electronics, TU Wien, Floragasse 7, 1040 Vienna, Austria

Resume : Utilizing a thermally induced exchange reaction between single-crystalline Ge nanowires and Al contact pads, we achieved monolithic Al-Ge-Al nanowire heterostructures with atomically sharp interfaces. Integrating such NW heterostructures with various Ge segment lengths as active channels in electrostatically modulated back-gated field-effect transistor devices, we demonstrate the remarkable potential of Al-Ge-Al nanowire heterostructures for nanoelectronic and photonic applications. Devices with short Ge segment length operated at high electric fields show unambiguous signatures of an electrostatically tunable negative differential resistance (NDR) effect in Ge even at room temperature. Modulation of the transfer rates, manifested as a large tunability of the peak-to-valley ratio and the onset of impact ionization is achieved by the combined influences of electrostatic gating, geometric confinement and heterojunction shape on hot electron transfer and by electron-electron scattering rates that can be altered by varying the charge carrier concentration in the nanowire field effect transistors. Thus, the fabricated three-terminal devices could prove to be of great technological interest for operating future devices combining NDR and impact ionization with conventional FET technology. Based on Ge nanowires with diameters comparable to the Bohr radius (aGe = 24.3 nm), we demonstrate quantum ballistic transport in heterostructure devices with ultra-scaled Ge segment lengths of only 15 nm at room temperature. Room temperature operation is a key requirement for the practical application of quantum ballistic transport such as high- performance, low-power dissipating transistors operating at the upper limit of “ON”-state conductance or multivalued logic gates. With respect to photonic applications, photodetectors based on these Al-Ge-Al nanowire heterostructures showed unmatched internal gains exceeding 107 and responsivities as high as 10 A/µW at 532 nm wavelength. This extraordinary high photosensitivity allows for reducing the detector area i.e. the Ge segment length down to sizes at which ballistic transport occurs, thus enabling the first demonstration of an ultrahigh gain quantum ballistic Ge nanowire photodetector also working at room temperature.

Authors : Paola Ceroni, Francesco Romano, Giacomo Bergamini, Raffaello Mazzaro, Brian A. Korgel
Affiliations : Paola Ceroni; Francesco Romano; Giacomo Bergamini; Raffaello Mazzaro Department of Chemistry “Giacomo Ciamician”, University of Bologna Brian A. Korgel McKetta Department of Chemical Engineering and Texas Materials Institute, The University of Texas at Austin

Resume : Si nanocrystals (SiNCs) in the quantum size range (2-12 nm) can be made as viable light emitters with emission wavelength that can be tuned from the near-infrared (NIR) into the visible by decreasing their size. Covalent Si-to-carbon bonding offers the possibility of integrating organic dyes for the development of hybrid luminescent materials. H-terminated nanocrystals, produced by thermal disproportionation of silicon oxide, were used as a platform for co-passivation with dodecene and different organic chromophores, e.g. pyrene,[1] porphyrin,[2] or benzothiadiazole chromophores.[3] Excitation of the organic chromophores results in an efficient energy transfer to the nanocrystal core: this is the working principle of a light harvesting antenna. This approach enabled us to circumvent the drawback of the low molar absorption coefficient of SiNCs. The investigated hybrid material exhibits high quantum yield also in the NIR spectral region with lifetime in the µs range. This research has potential applications in bioimaging, taking advantage of time-gated luminescence microscopy to enhance image resolution and in solar energy conversion: we are currently investigating the application of SiNCs in luminescent solar concentrators. [1] J. Phys. Chem. Lett. 2014, 5, 3325; Chem. Mater. 2015, 27, 4390. [2] Faraday Discussion 2015, 185, 481. [3] Chem. 2017, 2, 550.

Authors : F. Ehré(1), C. Dufour(1), F. Gourbilleau(1), J. Cardin(1), X. Portier(1), B. Garrido(2), O. Blazquez(2), W. M. Jadwisienczak(3), A. L. Richard(4), David C. Ingram(4) and C. Labbé(1)
Affiliations : (1) CIMAP, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, 6 Blvd Maréchal Juin 14050 Caen Cedex 4, France (2)MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona, Martí i Franquès 1, E 08028, Barcelona, Spain. (3)School of Electrical Engineering and Computer Science, Ohio University, Stocker Center, Athens, OH 45701, USA (4)Department of Physics and Astronomy, Ohio University, Athens, OH 45701, USA

Resume : Due to its 5d-4f transition, the Cerium ion has an important absorption cross section compare to its other rare earth counterparts. In addition, Ce3+ ion 5d band has an energy levels continuum giving thus wide energy absorption bands for an intense blue emission. Such emission could be applied for Light Emitting Devices (LEDs) generating strong visible blue light with a Si-based matrix compatible with CMOS technology. In the past, a strong Ce3+ ion emission has been detected with a cerium doped SiO2 host matrix. Nevertheless, this system suffers from low rare earth elements solubility as well as the lack of practical material durability after several carrier injections. One of the advantages to use a Si3N4 matrix is the reduction rare earth elements clustering compare to the SiO2. Moreover, such a nitride matrix offers larger electrical carriers injection due to a smaller band gap with respect to the oxide. In order to keep both advantages, a Ce doping SiOxNy matrix is investigated. The aim of this study is to elaborate MOS-LED structure based on Ce3+ doped SiOxNy films. The SiOxNy: Ce3+ layers are deposited on silicon substrates by using RF sputtering technique under N reactive flow. The effect of the matrix composition on carrier injection and transport in fabricated SiOxNy: Ce3+ MOS-LED structures will be investigated and the electroluminescence (EL) properties including I-V characteristic and EL spectra will be analyzed.

Authors : Katerina Dohnalova-Newell, Bart van Dam
Affiliations : Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands

Resume : Photoluminescence quantum yield (QY) methodology offers seemingly simple and robust way of assessing the emission efficiency in light emitting materials, such as dyes or semiconductor quantum dots (QDs). Using already standardized and widely used integrating sphere (IS) technique, it has been accepted as the standard methodology even in the industry. Here we show, for the first time, that the very same QY methodology suffers from a critical artifact, independently of the specific implementation, as soon as sample's absorption is compared to a blank reference. This artifact shows as QY dependence on absorption below certain absorption threshold - The lower the absorption, the more are the QY values underestimated. This happens as soon as the uncertainty in the number of measured absorbed photons is approximately 1/10th of the absorption of the sample - e.g. for uncertainty in measured number of absorbed photons of 1%, samples with absorption below 10-15% are already affected and underestimation in QY value is more than 200%. In general, we conclude that every study, where QY of samples with different absorption is compared, is affected, which means that this artifact has been influencing number of published studies (e.g. Nature Nanotechnology 6 (2011) 710, and many others), rendering their conclusions flawed. Using our theoretical simulations, we suggest modified QY methodology with an additional calibration protocol, which needs to be used in every case when QY of samples with varying absorption is evaluated and interpreted.

Authors : A. Iskandar, A. Gwiazda, M. Kazan, A. Bruyant, M.Tabbal, G. Lerondel
Affiliations : Department of Physics, American University of Beirut, P.O. Box 11-0236, Riad El-Solh, Beirut 1107-2020, Lebanon; Laboratoire de Nanotechnologie et d’Instrumentation Optique, ICD, CNRS UMR 6281, Université de Technologie de Troyes, 10010 Troyes, France

Resume : In this work, we demonstrate that phonons and photons of different momenta can be confined and interact with each other within the same nanostructure. The interaction between confined phonons and confined photons in silicon resonators arrays is observed by means of Raman spectroscopy. The Raman spectra from large arrays of dielectric silicon resonators exhibited Raman enhancement accompanied with a downshift and broadening. The analysis of the Raman intensity and line shape using finite-difference time-domain simulations and a spatial correlation model demonstrated an interaction between photons confined in the resonators and phonons confined in highly defective regions prompted by the structuring process. It was shown that the Raman enhancement is due to collective lattice resonance inducing field confinement in the resonators, while the spectra downshift and broadening are signatures of the relaxation of the phonon wavevector due to phonon confinement in defective regions located in the surface layer of the Si resonators. We found that, as the resonators increase in height and their shape becomes cylindrical, the amplitude of their coherent oscillation increases and hence their ability to confine the incoming electric field increases.

Session 5: Nanowires : Y. Roizin
Authors : Maria Josè Lo Faro1
Affiliations : 1 MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania, Italy;

Resume : Silicon nanowires (NWs) attracts the interest of the scientific community as building blocks for a wide range of future nanoscaled devices. We optimized the synthesis of NWs with a cheap, fast and maskless approach compatible with Si technology by using a chemical etching of Si substrates catalyzed by thin metal layers. NWs realized by this technique exhibit a bright room temperature emission, whose wavelength can be tuned with the NW diameter according to quantum confinement. Low-cost 2D random fractal arrays of vertically aligned Si NWs are obtained by engineering the deposition of fractal Au layers, without any lithography nor masks. The optical response of the system is controlled by the optimization of the NW fractal geometries. Strong in-plane multiple scattering and efficient light trapping overall the visible range are observed due to the fractal structure, remarking the promising potential of Si NWs. These strongly diffusing Si NWs allowed the first experimental observation of a new phenomenon of Raman coherent backscattering, exploiting the role of phase coherence in multiple scattering. Moreover, room temperature bright light emission from Si NWs promoted the realization of light emitting devices, multiwavelength hybrid light sources and of an innovative class of label free optical biosensors, opening the route towards low-cost integrated Si-based photonics and sensing.

Authors : Daryoush Shiri, Amit Verma, Reza Nekovei, Andreas Isacsson, C. R. Selvakumar, M. P. (Anant) Anantram
Affiliations : Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden; Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas 78363, USA; Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas 78363, USA; Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500, USA

Resume : Using Density Functional Theory (DFT), semi-empirical 10 orbital Tight Binding (TB) method and Ensemble Monte Carlo (EMC) simulations we show for the first time that (a) Gunn-Hilsum Effect can be induced in silicon nanowires (SiNWs) with diameters of 3.1 nm under 3 % tensile strain and an electric field of 5000 V/cm, (b) the onset of negative differential resistivity (NDR) in I-V characteristics is reversibly adjustable by strain and (c) strain can modulate the value of resistivity by a factor 2.3 for SiNWs of normal I-V characteristics i.e. those without NDR. Results are explained using electron-phonon scattering mechanisms including both Longitudinal Acoustic (LA) and Optical (LO) phonons involving both inter-sub band and intra-sub band scattering events. It is noteworthy that the observed NDC is different in principle from Esaki-Diode and Resonant Tunneling Diode (RTD) type of negative I-V slopes which originate from tunneling effect. Gunn-Hilsum or Gunn Effect and its associated negative differential resistivity (NDR) emanates from transfer of electrons between two different energy bands in a semiconductor. If applying an electric field transfers electrons from an energy sub band of a low effective mass to a second one with higher effective mass, then the current drops. This manifests itself as a negative slope or NDR in the I-V characteristics of the device which is in essence due to the reduction of electron mobility. In sharp contrast to GaAs, bulk silicon has a very high energy spacing (~1 eV) between sub band minima which renders the initiation of transfer-induced NDR unobservable. However our theoretical observation of Gunn Effect in silicon nanowires are promising for applications in mechanically-tunable microwave oscillators, and electromechanical sensors.

Authors : S. Caccamo, A. La Magna, G. Mannino, S. Scalese, R. A. Puglisi
Affiliations : Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi Ottava Strada 5, Zona Industriale, 95121 Catania, Italy

Resume : Silicon nanowires (SiNWs) have been largely studied for application in nanoelectronics, photonics and sensors. In all cases the control of their doping has demonstrated to be crucial as well as difficult. The conventional doping methods, such as ion implantation, can be critical in nanostructures for the difficulty to achieve conformality and abrupt junctions, for the stochastic spatial distribution of the implanted ion and for the severe crystal damage. Other approaches such as the formation of amorphous doped layers over the NWs present the drawback of creating heterointerfaces increasing trapping effects at the junction. An innovative solution to make controlled and conformal doping at nanoscale without bulk or surfacial defects has been recently proposed. This method consists in forming one monolayer of dopant-containing molecules from liquid solutions. Junction depths as small as 5 nm with dopant peak concentrations of 1×1019 cm-3 ca for both p- and n-type doping have been obtained. The method is applied to an array of 1×1010 cm-2 dense SiNWs with 1µm length and diameters up to about 60nm. The optical functionality of the SiNWs array is characterized and it is found that it shows a total reflectance, mainly consisting of the diffuse component, of 10% thus indicating that either the SiNWs strongly absorb the radiation or, alternatively, they have a relevant role in light trapping. The electrical characteristics of SiNWs doped by using the molecular doping are obtained for different junction depths and it is found that the molecular doping method applied to the SiNWs array provides efficient nanostrictured diodes.

Session 6: Sensing Platforms : F. Priolo
Authors : Philippe M. Fauchet
Affiliations : Department of Electrical Engineering Vanderbilt University Nashville, TN 37235-1826 USA

Resume : Resonant devices based on photonic crystal microcavities have been proposed and demonstrated in the silicon-on-insulator platform over the last decade. New geometries continue to be developed, which expand the potential domains of application. This presentation will review the evolution of such devices including some that have been demonstrated very recently. Application in biosensing will be discussed.

Authors : Deshraj Meena, M. C. Bhatnagar
Affiliations : Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016; Delhi Technological University, Shahbad, New Delhi, 110042

Resume : Since last decade synthesis and characterization of composite metal oxides nanostructures and finding their new applications has become an active research field. Cadmium Tin Oxide (CTO), cadmium stannate is one of the promising composite oxide system among other composite oxides like ITO, FTO, ZTO, etc. because of its peculiar and interesting optical and electrical properties[1].CTO system usually forms two polymorphs namely as mono and di cadmium stannate CdSnO3 and Cd2SnO4 respectively and both are transparent semiconductor oxides [1,2]. Cd2SnO4 has high carrier charge density in the range of 1018 to 1021 cm-3 and high mobility in the range of 10-100 cm2V-1S-1 and its wide optical band gap make it very promising material for the applications such as a TCO substrate in solar cells [3], photoanode material for solar water splitting system, biodegradation process [3,4]. It has been also explored for Li ion battery and dye sensitized solar cells applications [6]. Interestingly no one has explored the gas sensing properties of Cd2SnO4, while CdSnO3 has shown quite attractive gas sensing properties to various gases such as ethanol, chlorine, ammonia [7,8]. Herein we synthesized pure single phase orthorhombic Cd2SnO4 nanoparticles of cubical morphology by one step solution combustion method using stannous chloride and cadmium nitrate as precursor and citric acid is used as fuel. The structural and morphological properties of the synthesized nanoparticles were investigated using techniques such as X-ray diffraction, and FESEM, TEM. The XRD result of synthesized nanoparticles confirms the pure orthorhombic phase of the particles and morphological study using FESEM and TEM images confirm their uniform growth and cubical shape with edge length around 80 nm. Elemental composition of the synthesized nanoparticles was investigated using Energy-dispersive X-ray spectroscopy measurement. EDX results confirm the synthesized nanoparticles contains Cd and Sn in 2:1 ratio with excess of oxygen without any other impurities. Raman Spectrum obtained at room temperature also investigated of the synthesized nanoparticles. We further investigate the gas sensing properties of the synthesized nanoparticles at three different temperature for the ethanol, acetone, and ammonia gases. Our study suggest that the orthorhombic phase Cd2SnO4 has better sensitivity and response time for ethanol gas than the other gases at all three temperatures. We also suggest the gas sensing mechanism of the synthesized nanoparticles for the ethanol.The gas sensing properties were investigated on the principle of change in resistance of the sensor when exposed to the gas and the change depends on the type and concentration of the gas. The sensitivity of the sensor defined as ΔR/Ra where ΔR is change in resistance of the sensor and Ra is the resistance of the sensor in air. References 1. R.D. Shannon, J.L. Gillson, R.J. Bouchard J.Phys. Chem. Solids, 38, 877-881, (1977). 2. G.Haacke, H. Ando, W.E. Mealmaker J. Electrochem Soc.;SOLID STATE SCIENCE AND TECHNOLOGY, 124, 1923-1926 (1977). 3. Sarika A. Kelkar Energy Environ. Sci., 5, 5681-5685 (2012). 4. Sarika Kelkar, Chinmai Ballal, Aprna Deshpande, Sambhaji Warale, and Satishchandra Ogale, J. Mater.Chem. A, 1, 12426-12431 (2014). 5. Y. Sharma et al. Journal of Power Sources 192, 627–635 (2009). Gayatri Natu , Yiying Wu J. Phys. Chem. C 114, 6802–6807, (2010). 6. S. Dinesh , Material Science and Engineering B, 214, 37-45, (2016). 7. Chu Xiangfeng, Cheng Zhiming Sensors and Actuators B 98, 215-217, (2004). 8. Arijit De and Susmita Kundu Journal of Materials Engineering and Performance 25, 2746–2751 (2016)

Authors : A.A. Leonardi1,2,3,4, M.J. Lo Faro4,2, C. D’Andrea2, B. Fazio2, P. Musumeci1, C.Vasi2, G. Franzò4, S. Petralia5, E. Sciuto5, G. Palazzo6, S. Conoci5, L.Torsi6, F. Priolo1,4,7, A. Irrera2
Affiliations : 1 Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 2 CNR-IPCF, Istituto per i Processi Chimico-Fisici, V.le F. Stagno D’Alcontres 37, 98158 Messina, Italy; 3 INFN sezione di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 4 MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania, Italy; 5 STMicroelectronics, Stradale Primosole 50, 95121 Catania Italy; 6 Dipartimento di Chimica- Università degli Studi di Bari “Aldo Moro”Via Orabona 4, 70126, Bari; 7 Scuola Superiore di Catania, Via Valdisavoia 9, 95123 Catania, Italy;

Resume : Silicon nanowires (NWs) are attracting the scientific community for a wide range of application. The realization of a new class of luminescence biosensors based on Si NWs for protein and DNA is demonstrated. These sensors are based on the quenching of the PL signal due to the quantum confinement at room temperature of ultrathin Si NWs. The occurrence of non radiative phenomena introduced by the target analyte on the NW surface determines the quenching of the PL signal. In particular, we realized a sensor for C-reactive protein (CRP), which is crucial for heart-failure pathology. The availability of high sensitivity, low-cost and reliable CRP sensors is a priority demand in clinical diagnosis for cardiovascular diseases. Si NW sensors are fast, highly selective and offer a broad concentration dynamic range. Moreover, these sensors reach a fM sensitivity permitting non-invasive analysis in saliva (1). By changing the functionalization protocol, we realized a label- and PCR-free sensor capable to reveal few copies of Hepatitis B virus without amplification of the DNA and endowed with a strong selectivity. Si NWs open the route towards new optical label-free sensors with low cost and a full industrially compatible approach for the primary health care diagnosis. 1.”New Generation of Ultrasensitive Label-Free Optical Si Nanowire-Based Biosensors”, ACS Photonics, 10.1021/acsphotonics.7b00983, 2017

Session 7: Light emitting materials : A. Irrera
Authors : G. Mula(1,2), T. Printemps(3,4), C. Licitra(3,4), E. Sogne(5), F. D’Acapito(6), N. Gambacorti(3,4), N. Sestu(1), M. Saba(1), E. Pinna(1,2), D. Chiriu(1), P. C. Ricci(1), A. Casu(5), F. Quochi(1), A. Mura(1), G. Bongiovanni(1), A. Falqui(5)
Affiliations : 1 Dipartimento di Fisica, Università degli Studi di Cagliari, S.P. 8 km 0.700, 09042, Monserrato (Ca), Italy; 2 CNR-IOM, Unità di Cagliari SLACS, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Monserrato, Italy; 3 Université Grenoble Alpes, F-38000, Grenoble, France; 4 CEA, LETI, MINATEC Campus, F-38054, Grenoble, France; 5 King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering (BESE) Division, Nabla Lab, Thuwal, 23955-6900, Saudi Arabia; 6 CNR-IOM- OGG c/o ESRF, LISA CRG, 71 Av. des Martyrs, F-38043, Grenoble, France.

Resume : The successful light emission from silicon devices is one of the big challenges for optoelectronics and telecommunications, that if won will allow a significant reduction of the costs and fabrication times. Many research groups have investigated for years a way to obtain efficient light emission at 1,5 m from rare earth-doped silicon samples. Unfortunately, Er clustering turned out as a limiting factor in obtaining a sufficient optical gain in Er-doped Si materials. To overcome this issue, we propose a new paradigm for porous silicon structures: moving from Er doping to Er filling. As a matter of fact, looking for an equilibrium between Er content and light emission using 1-2% Er is a dead end road for efficient photoluminescence (PL), given that an insufficient Er content and/or the Er clustering will act as strong limiting factors. In this study, we used a multidisciplinary approach mainly based on needle electron tomography (ET), electrochemistry, EXAFS, PL and electron microscopy. We demonstrate that the pore filling approach leads to enhanced PL emission, with respect to standard Er doping, and that this emission originates from both erbium oxide and silicate. These results then help identifying where to address the efforts towards highly efficient Er-related emission from porous Si. REFERENCES: [1] G. Mula et al. Sci. Rep. 7 (2017), 5957; [2] G. Mula et al. Appl. Surf. Sci. 311, 252–257 (2014); [3] G. Mula et al. J. Phys. Chem. C 116, 11256 (2012).

Authors : Alessio Palavicini and Chumin Wang
Affiliations : Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510, Mexico City, Mexico

Resume : An omnidirectional mirror that works for a wide range of light frequencies and all incidence angles is a basic element for infrared communication. In this work, we report a hybrid quantum-classical design of a dielectric multilayer device consisting of an ab initio calculation of the dielectric function for each semiconducting layer with a specific atomic structure [1], followed by a study of wave scattering through the device using the transfer matrix method within the classical electromagnetic theory. The designed omnidirectional mirror consists of stacked multilayer reflectors, each one tuned to a portion of the reflection band. The validation of this design was carried out on a freestanding nanostructured porous silicon multilayer film fabricated by electrochemical etching of a highly-doped p-type [100]-oriented crystalline Si wafer alternating two anodic current densities and finishing with a high current to separate the multilayer from the substrate [2]. The measured infrared transmittance spectra are compared with those predicted from the multiscale design. Finally, we think that multiscale studies based on ab-initio calculations could be a useful alternative for the design of photonic devices. This work has been supported by CONACyT-252943 and UNAM-IN106317. A. P. acknowledges the financial support from PAEP of UNAM. [1] P. Alfaro, A. Palavicini and C. Wang, Thin Solid Films 571, 206 (2014). [2] A. Palavicini and C. Wang, Optics and Photonics Journal 3, 20 (2013).

Authors : Viktoriia Rutckaia, Mihail Petrov, Alexey Novikov, Mikhail Shaleev, Frank Heyroth, Vadim Talalaev, and Joerg Schilling
Affiliations : Viktoriia Rutckaia; Vadim Talalaev; Joerg Schilling - Centre for Innovation Competence SiLi-nano, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany Mihail Petrov - Department of Nanophotonics and Metamaterials, ITMO University, St. Petersburg, Russia Alexey Novikov; Mikhail Shaleev - Institute for Physics of Microstructures of the Russian Academy of Sciences (IPM RAS), 603950 Nizhniy Novgorod, Russia Frank Heyroth - Interdisciplinary center of material science, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany

Resume : CMOS-compatible light emitters are intensely investigated for integrated active silicon photonic circuits. One of the approaches to achieve on-chip light emitters is the epitaxial growth of Ge(Si) QDs on silicon. Their broad emission in 1.3-1.5 um range is attractive for the telecomm applications. We investigate optical properties of Ge(Si) QD multilayers, that are grown in a thin Si slab on a SOI wafer, by steady-state and time-resolved micro-photoluminescence. We identify Auger recombination as the governing mechanism of carrier dynamics in such heterostructures. Then we demonstrate the possibility of light manipulation at the nanoscale by resonant nanostructures investigating Si nanodisks with embedded Ge(Si) QDs. We show that the Mie resonances of the disks govern the enhancement of the photoluminescent signal from the embedded QDs due to a good spatial overlap of the emitter position with the electric field of Mie modes. Furthermore we engineer collective Mie-resonances in a nanodisk trimer resulting in an increased Q-factor and an up to 10-fold enhancement of the luminescent signal due to the excitation of anti-symmetric magnetic and electric dipole modes. Using time-resolved measurements we show that the minima of the radiative lifetime coincide with the positions of the Mie resonances for a large variation of disk sizes confirming the impact of the Purcell effect on QD emission rate. Purcell factors at the different Mie-resonances are determined.

Authors : Cintia Ezquerro, Elisa Fresta, Elena Serrano, Rubén D. Costa, Elena Lalinde, Jesús. R. Berenguer, Javier García-Martínez
Affiliations : Cintia Ezquerro, Elena Lalinde, Jesús R. Berenguer Dpt. Química, Facultad de Ciencia y Tecnología, Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006, Logroño, Spain. Elisa Fresta, Rubén D. Costa Hybrid optoelectronic materials and devices. IMDEA Materiales.28906, Getafe, Madrid, Spain. Elena Serrano, Javier García-Martínez Molecular Nanotechnology Lab. Dpto. Química Inorgánica. Universidad de Alicante, Ctra. San Vicente s/n, E-03690, Alicante, Spain.

Resume : The search of efficient sources of white artificial illumination has become increasingly widespread in the last years, driving to the development of new hybrid inorganic/organic emitting diodes (WHLEDs) architectures.[1] Following with our research in the design of hybrid luminescent materials,[2] here we report the synthesis of new monochromatic- or the first white-emitting hybrid organometallo-silica nanoparticles. These latter have been prepared using a new synthetic approach consisting of the generation of a central nanobundle, built from the condensation of three different emitting complexes ([Ir(dfppy)2(PPETS)2]OTf, [Ir(ppy)2(PPETS)2]PF6, [Ir(ppy)2(dasipy)]OTf), previous to the formation of the mesoporous silica shield. These emitting nanoparticles have been implemented into a rubber-like coating and tested on top of a UV-LED, providing HLEDs with a very efficient white emission, which is stable over thousands of hours and mimics quite well the visible part of the sunlight spectrum. 1. L. Niklaus, S. Tansaz, H. Dakhil, K. T. Weber, M. Pröschel, M. Lang M. Kostrzewa, P. B. Coto, R. Detsch, U. Sonnewald, A. Wierschem, A. R. Boccaccini and R. D. Costa, Adv. Funct. Mater. 2017, 27, 1601792. 2. C. Ezquerro, A. E. Sepulveda, A. Grau-Atienza, E. Serrano, E. Lalinde, J. R. Berenguer, J. Garcia-Martinez, J. Mater. Chem. C 2017, 5, 9721

Authors : I. Shahine 1)*; J-J. Gaumet 1); A. En-Naciri 1); P. Miska 2); B. El-Eulmi 2); H. Rinnert 2); and S. Akil 1)
Affiliations : 1) Laboratoire de Chimie et Physique , Université de Lorraine 1 Bd. Arago, 57070 Metz (France); 2) Université de Lorraine, UMR CNRS 7198, Institut Jean Lamour, BP 70239, 54506 Vandœuvre-lès-Nancy, France

Resume : The construction of a semiconductor heterojunction has attracted a lot of attention due to its perfect effectiveness in improving the sensing, luminescence and photocatalytic activity of a wide range of nanomaterials. [1-3] In particular, hybrid nanostructures composed of semiconductor (SC) and metallic nanoparticles (MNP) have received growing interest due to the high confinement associated to the plasmonic resonances of MNP. This phenomenon enables strong interactions with other photonic elements such as quantum emitters. [4] The resulting plasmon-exciton interaction gave benefits to a wide range of applications such as gas and vapor sensing, hydrogen storage, electro-optics, and catalysis. In this context, we develop a metal-semiconductor nanomaterial (Au-ZnO and Ag-ZnO) using a new synthesis method which is green, simple and exhibiting high quantum yield and good stability nanomaterials. The first step was the synthesis of ZnO nanoparticles by a hydrothermal process in order to tune their photo-luminescence properties based on optical and structural characterization using UV-Visible spectroscopy, Differential scanning calorimetry (DSC), photoluminescence (PL) and Transmission electron microscopy (TEM). In this communication, we show results about the synthesis of ZnO nanocrystals and some ones about the hybrid nanoparticles. References [1] Jiang, R., Li, B., Fang, C., & Wang, J. (2014). Advanced Materials, 26(31), 5274-5309. [2] Wang, X., Chen, X., Thomas, A., Fu, X., & Antonietti, M. (2009). Advanced Materials, 21(16), 1609-1612. [3] Zhang, L., Wong, K. H., Chen, Z., Jimmy, C. Y., Zhao, J., Hu, C. & Wong, P. K. (2009). Applied Catalysis A: General, 363(1), 221-229. [4] Alvarez-Puebla, R., Liz-Marzan, L. M., & Garcia de Abajo, F. J. (2010). The Journal of Physical Chemistry Letters, 1(16), 2428-2434.

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Session 8: Material processing and defect engineering : H.H. Radamson, A. Ruzin
Authors : W. Skorupa, L. Rebohle, S. Prucnal, Y. Berencén, S. Zhou, M. Helm
Affiliations : Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany

Resume : One of the main issues in semiconductor research is doping and crystallization. To meet the high standards of today’s microelectronic industry, especially in the context of nanostructures, more and more non-equilibrium processing technologies has been entered. This applies, above all, to thermal processing which usually has to activate dopants and anneal out defects, but has to suppress diffusion and segregation at the same time. This presentation is focused on the use of millisecond flash lamp annealing (FLA) for advanced thermal processing of group-IV materials including Si, Ge and GeSn alloys. FLA is able to exceed the solid solubility limit of dopants which is discussed for the cases of P and Sn in thin Ge films as well as for Se in Si nanowires. Moreover, the specific conditions of FLA determine whether a thin amorphous film on a crystalline substrate, e.g. an amorphous Ge layer on Ge after ion implantation, recrystallizes in a poly- or monocrystalline way. Finally, perspectives of FLA for other materials will be presented.

Authors : S. Geiskopf (1), M. Stoffel (1), X. Devaux (1), E. André (2), C. Carteret (2), A. Bouché (1), M. Vergnat (1), H. Rinnert (1)
Affiliations : (1) Université de Lorraine, UMR CNRS 7198, Institut Jean Lamour, BP 70239, 54506 Vandœuvre-lès-Nancy, France (2) Université de Lorraine, UMR CNRS 7564, LCPME, 405 rue de Vandœuvre, 54600 Villers-lès-Nancy, France

Resume : Si nanocrystals (Si-NCs) embedded in dielectric matrices have been extensively studied due to potential applications in novel opto- or nanoelectronic devices. To reach this goal, a deep understanding of the electrical doping of Si-NCs is, however, mandatory. Both theoretical and experimental studies have shown the possibility to dope Si-NCs with either Boron (B) or Phosphorus (P). However, the exact location of the dopants in the heavy doping regime has received only little attention up to now. In this work, we investigate heavily phosphorus doped SiO1.5 thin films prepared by evaporation under high vacuum. The films were prepared by co-evaporation of both SiO and SiO2 from e-beam guns while phosphorus was supplied by a GaP decomposition source. The structural and optical properties were studied by means of X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), Raman and Fourier transform infrared (FTIR) absorption spectroscopies. For thin films annealed at 1100°C, we provide clear experimental evidence of the formation of both SiP2 and SiP nanoparticles crystallizing in an orthorhombic structure. The overall nanoparticle size increases with the P doping from about 15 to 35 nm. STEM characterizations combined with energy dispersive X-ray spectroscopy measurements indicate that most of the nanoparticles consist of SiP2. This is consistent with Raman measurements and with density functional theory calculations of the SiP2 vibrational properties.

Authors : B. Pivac1, P. Dubček1, S. Bernstorff2
Affiliations : 1 Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia 2Elettra-Sincrotrone Trieste, SS 14, km 163.5, Basovizza (TS), Italy,

Resume : It has been shown that Ge nanoparticles (NPs) embedded in transparent dielectric matrix have properties different from the respective bulk semiconductor and present a great potential for application in electronic and optoelectronic devices. Due to quantum confinement properties of materials can be tuned by varying the nanoparticle size. These properties may be exploited for the fabrication of nanoscale electronic devices or advanced solar cells. Nevertheless, properties of the composite material involving NPs are not yet completely understood. In this work we explored the structural and interface characteristics of Ge NPs formed in SiC matrix. Magnetron cosputtering was used for deposition from Ge and SiC solid source, and upon suitable thermal treatment a superstructure of NPs embedded in dielectric was formed. The structural properties were explored by GISAXS/GIWAXS and Raman analysis. All techniques were used to obtain information on crystallinity, size and shape of the grown objects. Moreover, the Porod analysis of the GISAXS pattern was carried to get additional insight in the NPs / matrix interface. The results will be compared with EPR measurements. We shall explore how such layer affects PL properties of NPs.

Authors : Dongke Li, Yicheng Jiang, Jiaming Chen, Jun Xu*,Pei Zhang, Wei Li, Kunji Chen
Affiliations : School of Electronic Science and Engineering and National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Nanjing University, Nanjing, 210000, China.

Resume : Doping in Si nanocrystals (Si NCs) is a fundamental issue in order to develop the next generation nano-electronic and opto-electronic devices. However, achieving efficient doping in Si NCs is quite difficult since the impurities tend to be expelled from the inner sites of dots. Moreover, the introduced dopants, such as Phosphorus (P) and Boron (B) in Si NCs, exhibit the novel doping behaviors as studied previously . We have demonstrated experimentally that the phosphorus (P) dopants could incorporated into Si NCs substitutionally after passivating interface states of Si NCs in Si NCs/SiO2 multilayers. In the present work, we study the influences of P doping and P/B co-doping on the electronic and luminescence properties in Si NCs/SiO2 multilayers. It is found that the luminescence intensity around 820nm of P doped samples are enhanced by 19.4% comparing with the un-doped one which can be attributed to the P passivation effect and the nonlinear optical absorption properties of Si NC were also tuned through modifying interface states. Further, in the P/B co-doped Si NCs/SiO2 multilayers, the P doping efficiency is promoted with controlling the B co-doping level. The subband luminescence is also enhanced by co-doping. Our results suggest a new route to modulate the electronic structures and opto-electronic characteristics of Si NCs for device applications. This work is supported by NSFC (No. 11774155) and PAPD.

Authors : G. Briere, P. Ni, S. Héron, P. Genevet
Affiliations : Université Côte d’Azur, CNRS, CRHEA, rue Bernard Gregory, Sophia Antipolis 06560 Valbonne, France

Resume : The common way to manipulate light consists in using classical optical elements such as lenses and mirrors. Since few years, a new way to manipulate light with two dimensional optical components, also known as optical meta-surfaces, have been exploited to control light propagation using local phase discontinuities. Owing to their reduced thicknesses and their high order of transmission in the visible, metasurface components would enable the next generation of flat optical devices. In this work, we present innovative semiconductor based metasurfaces and discuss GaN-metasurfaces manufacturing processes relevant for electronics and optoelectronics industrial applications, e.g. light-emitting diode (LED) or high-electron-mobility-transistor (HEMT).

Authors : E. Simoen1,2, P.C. Hsu1,3, D. Boudier4, B. Cretu4, G. Eneman1, N. Collaert1, C. Claeys3
Affiliations : 1Imec, Kapeldreef 75, B-3001 Leuven, Belgium 2Ghent University, Krijgslaan 281, B-9000 Gent, Belgium 3KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium 4 Normandie Univ, UNICAEN, ENSICAEN, CNRS, GREYC, 14000 Caen, France

Resume : Crystalline defects in semiconductor materials have always played an important role in the charge transport: when electrically active, they give rise to energy levels in the band gap, which serve as stepping stones for carrier recombination and generation, thus determining the lifetime. Even when they are inactive, the presence of neutral defect centers can cause scattering events, thereby affecting the carrier mobility. When entering the regime of nanodevices, the impact of defects becomes even more pronounced, as is well-known from the so-called Random Telegraph Noise (RTN) often observed in scaled MOSFETs [1]. At the same time, novel quantum effects can be amplified by the presence of defects, giving rise to potential new applications [2]. Here, the impact of single defects on the operation and the reliability of several types of devices will be discussed. Firstly, it is shown that single defect centers in Ultra-Thin Buried Oxide (UTBOX) Fully Depleted Silicon-on-Insulator (FD SOI) nMOSFETs can give rise to pronounced generation-recombination (GR) noise in the frequency domain, corresponding with RTN in the time domain [3]. It will be demonstrated that these defects play a crucial role in the retention time of single-transistor memories fabricated in UTBOX SOI [4]. Moreover, studying the characteristic frequency as a function of temperature enables to perform noise spectroscopy and assists in the identification of the deep levels, which are mainly processing induced [5]. These GR noise studies can be extended to the case of nanowire SOI FETs or to nanoscale fin-type of transistors, fabricated with so-called high-mobility channel materials (Ge, III-V) [6,7]. Similar RTN phenomena will be shown for scaled Resistive Random Access Memory (RRAM) devices based on high- dielectrics [8]. While the effects of single defects on the DC and AC transport can be experimentally assessed in a quite straightforward manner, one of the challenges is the identification of their origin. Therefore, a strategy will be discussed to tackle this challenge, which consists of a combination of spectroscopic studies on large-area devices, delivering the necessary defect parameters to implement in a Technology Computer-Aided Design (TCAD) simulation of the current-voltage characteristics of nanoscale devices [9]. [1] E. Simoen and C. Claeys, “Random Telegraph Signals in Semiconductor Devices”, Institute of Physics Publishing, Bristol, UK (2016). [2] L. Ma, W. Han, W. Hong, Q. Lyu, X. Yang and F. Yang, J. Appl. Phys. 117, 034505 (2015). [3] E. Simoen, M. Aoulaiche, S. D. dos Santos, J.A. Martino, V. Strobel, B. Cretu, J.-M. Routoure, R. Carin, A. Luque Rodríguez, J.A. Jiménez Tejada and C. Claeys, ECS J. of Solid St. Science and Technol. 2, Q205 (2013). [4] M. Aoulaiche, E. Simoen, C. Caillat, L. Witters, J. Martino, C. Claeys, P. Fazan and M, Jurczak, Solid-State Electronics 117, 123 (2016). [5] D. Boudier, B. Cretu, E. Simoen, A. Veloso, N. Collaert and A. Thean, Solid-St. Electron. 128, 109 (2017). [6] A. V. Oliveira, E. Simoen, J. Mitard, R. Langer, P. G. D. Agopian, J. A. Martino, L. Witters, A. Thean and C. Claeys, IEEE Electron Device Lett. 37, 1092 (2016). [7] L. He, E. Simoen, C. Claeys, H. Chen, D. D. Guo, L. N. Hu and Y. Qin, in the Proc. of ICNF 2017, Vilnius (Lithuania), 20-23 June 2017, IEEE Explore doi: 10.1109/ICNF.2017.7985987. [8] J. Ma, Z. Chai, W. Zhang, J. F. Zhang, Z. Ji, B. Benbakhti, B. Govoreanu, E. Simoen, L. Goux, A. Belmonte, R. Degraeve, G. Kar and M. Jurczak, submitted to IEEE Trans. Electron Devices. [9] K. Ni, G. Eneman, E. Simoen, R. Schrimpf, R. Reed, D. Fleetwood, N. Collaert and A. Thean, IEEE Trans. Electron Devices 63, 3069 (2016).

Authors : O. Madia(a), J. Kepa(a), V. V. Afanas’ev(a), J. Franco(b), B. Kaczer(b), A. Hikavyy(b), A. Stesmans(a)
Affiliations : a- Semiconductor Physics Laboratory, University of Leuven, Belgium; b- IMEC, Leuven, Belgium

Resume : Interface dangling bonds (DBs) critically affect reliability of metal/insulator/Si devices by providing charge traps upon bias-temperature stressing. It is found, however, that adding Ge to the channel layer significantly improves the reliability and the lifetime of transistors enabling scaling to the 10 nm node and beyond. In order to get insight in the nature of this beneficial effect we analyzed DBs in Si-passivated (1- or 3-nm thick Si cap) strained-(100)Si1-xGex (x=0.25-0.55) layers at interfaces with 1.8-nm thick HfO2 dielectrics by using Electron Spin Resonance (ESR). The results suggest Si DBs (Pb0 centers) located at the interface between the Si substrate and the pseudomorphic Si1-xGex film to be the dominant defects. The density of Si DBs in the Ge containing samples is significantly lower than at the reference (100)Si/ HfO2 interface and decreases below the ESR detection limit (≈1x1011cm-2) with increasing thickness and Ge concentration in the Si1-xGex layer. However, the beneficial effect of Ge fades when the thickness of the Si cap is reduced to 1 nm or in the case of direct deposition of HfO2 on top of uncapped Si1-xGex. From these results we conclude that DBs are eliminated due to in-diffusion of Ge from the Si1-xGex channel into the Si substrate bringing the concentration of Ge to the range in which the generation of Si DBs becomes energetically unfavorable. This picture is in agreement with previous observations on condensation-grown Si1-xGex layers.

Authors : A. Bellucci, M. Girolami, M. Mastellone, S. Orlando, R. Polini, A. Santagata, and D. M. Trucchi
Affiliations : A. Bellucci, M. Girolami, M. Mastellone, R. Polini, D.M. Trucchi: Istituto di Struttura della Materia sez. Montelibretti, CNR - Via Salaria km 29.300 - Monterotondo (Rm) Italy; S. Orlando, A. Santagata: Istituto di Struttura della Materia sez. Tito Scalo, CNR - Contrada Santa Loja - Zona Industriale Tito Scalo (Pz) Italy; R. Polini: Dipartimento di Scienze Tecnologie Chimiche, Università di Roma “Tor Vergata”, Via della Ricerca Scientifica, 1 - Rome, Italy.

Resume : Silicon Carbide (SiC) is a wide bandgap semiconductor with superior properties, such as high dielectric strength, high thermal conductivity, high saturation velocity, and excellent physical and chemical stability. The demonstrated capability to work in harsh environment led to a rapid development of SiC based high-power electronic components and optoelectronic devices working in the ultraviolet. Nevertheless, maximum photo–responsivity in the range 240-380 nm makes SiC blind to solar radiation and does not allow an efficient exploitation of its physical properties in the solar energy conversion field. Here we demonstrate for the first time the enhancement of SiC optical absorptance obtained by femtosecond laser texturing of the surface. fs-laser pulses induce a periodic structure with a ripple period λr dependent on laser wavelength λ and material refractive index n according to λr = λ/(2n), able to drastically increase optical absorptance in the 200-2000 nm range. Moreover, we demonstrate the effectiveness of this treatment in introducing defect levels within SiC bandgap that, acting as an intermediate band, result in a significant enhancement of photo-generated current in the visible range. These outstanding results open the path for a successful exploitation of SiC for fabrication of future solar devices and for the development of efficient wide spectral range photodetectors.

Authors : Nai-Wen Hsu1*, Po-Yuan Chiu2, Chung-Tao Chou2, Yen Chuang1, Chia-You Liu1, Charles Thomas Harris3, Tzu-Ming Lu3, and Jiun-Yun Li1,2,4
Affiliations : 1 Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan 2 Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan 3 Sandia National Laboratories, Albuquerque, New Mexico 87185, USA 4 National Nano Device Laboratories, Hsinchu 30078, Taiwan *E-mail:

Resume : We demonstrated a two-dimensional electron gas (2DEG) in a strained Ge quantum well for the first time. The Ge 2DEG was formed on a modulation-doped Ge/ Ge0.82Si0.18 heterostructure, which were epitaxially grown by reduced pressure chemical vapor deposition. Two-dimensional electrons were confined in a Ge quantum well by the Ge0.82Si0.18 energy barriers. In-situ phosphorous doping was used for the growth of the remote electron supply layer, ~ 30 nm above the QW. We fabricated the Hall-bar devices to characterize the magneto-transport properties of Ge 2DEG and Hall measurements were performed at 4 K and 0.3 K. The density and mobility of Ge 2DEG are 2×〖10〗^11 cm-2 and 1,500 cm2/Vs, respectively at 4 K. Shubnikov-de Haas oscillations with an integer quantum Hall state of υ = 1 were observed at 0.3 K. This experimental result strongly suggests the existence of 2DEG in a Ge quantum well. Along with Ge two-dimensional hole gases (2DHGs), the realization of an electron-hole bilayer system on group Ⅳ heterostructures becomes possible. Acknowledgements This work at NTU has been supported by the Ministry of Science and Technology (106-2112-M-002-009-). This work at Sandia National Laboratories has been supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, US Department of Energy (DOE). This work was performed, in part, at the Center for Integrated Nanotechnologies, a US DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under Contract No.DE-NA-0003525.

Authors : R. Demoulin (1), M. Roussel (1), S. Duguay (1), P. Pareige (1), E. Talbot (1), D. Muller (2), D. Mathiot (2)
Affiliations : (1) Groupe de Physique des Matériaux, UNIROUEN, INSA Rouen, CNRS, 76000 Rouen, France; (2) ICube Laboratory, Université de Strasbourg and CNRS, B.P. 20, 67037 Strasbourg cedex, France

Resume : Materials consisting of silicon nanocrystals (Si-ncs) embedded in silicon dioxide (SiO2) are the subject of an intense research activity due to their numerous potential applications in the fields of optoelectronic and photonic. Moreover, the well-known and widely used process of impurity doping in such materials allows tailoring Si-based devices for a specific use. In fact, the n- or p-type dopants provide respectively electrons or holes that can significantly modify the electrical or optical properties of the materials. However, the efficiency of doped materials strongly depends on the dopant location in the host matrix. In this way, an accurate control of the dopant location is necessary in order to improve the quality of these systems. In this work, n- (P, As) and p-type (B) doping carried out by co-implantation with Si in SiO2 thin films annealed at 1100°C have been investigated using Atom Probe Tomography. In each cases, the 3D spatial distribution of Si and dopant atoms has been computed. It allowed us to study the structure of these films at the atomic scale to investigate the location of dopants and the Si clustering characteristics (size distribution, density, composition …) along the implantation profile. It has been shown that n-type dopants are efficiently introduced in Si-ncs while p-type dopant remains outside of Si-ncs. The effect of the dopant nature on the structural properties and its influence on the Si-ncs growth will be discussed.

Poster Session 2 : H. H. Radamson, A. Irrera, A. Ruzin, I. Berbezier
Authors : Abhijit Ray, Priyanka Marathey, Ranjan Kumar Pati, Indrajit Mukhopadhyay
Affiliations : Department of Solar Energy, Pandit Deendayal Petroleum University, Raisan, Gandhinagar, Gujarat 382-007, India

Resume : Semiconductors having smaller and direct band gaps such as CuO, NiO etc, which show p-type conductivity and favorable conduction band alignment for hydrogen evolution from water have recently attracted attention for application as photocathode in photoelectrochemical cells. In the present study we show that sensitizing their nanostructures with low cost organic dyes, such as Mercurochrome, Eosin Y and Rhodamine-B has significant effect in enhancing their photocurrent density and hence the efficiency of hydrogen evolution reaction from water. A carrier multiplication phenomenon by dual excitation in the dye-semiconductor system has been demonstrated. The development has the potential of application not only in the field of water splitting but also in dye sensitized solar cells and other photo-redox applications.

Authors : ShinYoung Jeong1,2, Soon-Kyu Cha1,3, Sungjun Kang4, and Il Ki Han1,3
Affiliations : 1: Nanophotonics Research Center, Korea Institute of Science and Technology, Seoul 02792; 2: School of Electrical Engineering, Korea University, Seoul 02841; 3: KHU-KIST Department of Converging Science and Technology, Kyunghee University, Seoul 02447; 4: Advanced Materials Engineering for Information & Electronics, Kyunghee University, Yongin 17104

Resume : As displays and imaging technologies become more sophisticated, development of sensors for the high-speed camera has become indispensable. Recently, image sensors for automatic operation of automobiles have become more attractive, so that not only the resolution of the sensor but also the response speed have become important. In this study, we have fabricated a vertical type photodiode using a quasi-type 2 colloidal quantum dot, which is advantageous for carrier extraction and exhibits a much faster response speed than a type 1 quantum dot. Depending on the type of ligand capping QDs, Oleic acid and MPA capped QDs showed τr = 77.6 ± 8.54 ns and τf =100 ± 14.70 ns, and τr = 28.8 ± 8.34 ns and τf = 40 ± 9.81ns, respectively. Short rise and fall times of MPA over Oleic acid capped QDs are due to short ligands in MPA than Oleic acid. A photodiode with type 2 QDs capped with MPA would be useful for the CMOS-compatible high-speed image sensors.

Authors : Sung Won Hwang
Affiliations : Konkuk University

Resume : Sapphire is widely used as a substrate for the growth of GaN epitaxial layer (EPI), but has several drawbacks such as high cost, large lattice mismatch, non-flexibility, and so on. Here, we first employ graphene directly grown on Si or sapphire substrate as a platform for the growth and lift-off of GaN-light-emitting-diode (LED) EPI, useful for not only recycling the substrate but also transferring the GaN-LED EPI to other flexible substrates. Sequential standard processes of nucleation/recrystallization of GaN seeds and deposition of undoped (u-) GaN/AlN buffer layer were done on graphene/substrate before the growth of GaN-LED EPI, accompanied by taping and lift-off of u-GaN/AlN or GaN-LED EPI. Upconversion photoluminescence (PL) from graphene quantum dots (GQDs) excited by the second-order diffraction light of wavelength λ/2 co-existing in the red light. Real upconversion PL from GQDs is observed under excitation with a femtosecond pulsed laser, implying that coherent photons with high enough power density can be upconverted into blue light via GQDs. This approach can overcome the limitations by the catalytic growth and transfer of graphene, and make the oxygen-plasma treatment of graphene for the growth of GaN EPI unnecessary. This work was supported by a grant to the Ministry of Trade, Industry & Energy (MOTIE, Korea) under Industrial Technology Innovation Program (no.10067533), Korea Evaluation Institute of Industrial Technology, Republic of Korea.

Authors : Jun Oh Kim, Tien Dai Nguyen, Sang Jun Lee
Affiliations : Korea Research Institute of Standards and Science

Resume : The short-wavelength infrared (SWIR) photodetectors can be used for a variety of applications such as gas analysis, humidity monitoring, telecommunication, and spectrometry. At present, the InGaAs and extended-InGaAs photodetector is the most widely used in the SWIR band (from 0.9 to 3 µm). The cut-off wavelength (λcutoff) of InGaAs and extended InGaAs is 1.7 μm and 2.65 μm, respectively. However, in this extended InGaAs material, metamorphic growth is required to overcome lattice differences in epitaxial growth. Although many improvements related to growth have taken place, the performance at room temperature is below par and cooling is needed for higher detectivity. In the past few decades, infrared photodetectors using Sb–based structure lattice–matched on GaSb substrate have been studied and several types were developed for SWIR detection. In particular, the barrier detectors are the ability to serve as dual–band infrared detectors. It is possible to design a dual–band detector that operates independently at different spectral regions based on the bias polarity. In this study, we present the results of investigations on a dual-band detector that was fabricated using lattice–matched III–V materials, GaSb and InGaAsSb, operating in the SWIR band at room temperature. The dual-band device was grown using molecular beam epitaxy (MBE) with As2 and Sb2 cracker sources on a GaSb substrate. The active region consist of two different materials, a 2–µm–thick In0.23Ga0.77As0.22Sb0.78 and 2–µm–thick GaSb layer, which are separated by a barrier of Al0.4Ga0.6Sb ternary with thickness of 100 nm. After the epi-layer growth, the device was processed in 410×410 µm2 mesas using inductively coupled plasma etching, followed by the contact metal deposition. The devices had a circular aperture of 300 µm in each mesa. Spectral response was measured using a Fourier transform infrared (FTIR) spectrometer (Nicolet Instrument, Inc.) at room temperature with illumination from the front side of the sample. The resulting structure has detection capability in the short-wavelength infrared ranges, cut-off wavelength of 1.6 μm (SWIR1; GaSb) and 2.65 μm (SWIR2; InGaAsSb) depending on the applied bias. The dual-band photodetector was evaluated by current–voltage (I–V) characteristics, spectral response, and detectivity (D*).

Authors : Salvatore Petralia1, Mario Urso, Emanuele L. Sciuto2, Salvatore Mirabella2, Francesco Priolo2 and Sabrina Conoci1
Affiliations : 1STMicroelectronics, Stradale Primosole, 50 – 95121 Catania, Italy 2MATIS CNR-IMM and Dep. of Phys. And Astron. University of Catania, Via S. Sofia 64 Catania, Italy.

Resume : A novel Silicon device composed by three integrated planar microelectrodes with the working electrode based on Nickel was developed and tested. A plastic board sealed on the top of silicon part forms electrochemical cell with a total volume of 20 µl. The sensing mechanism is based on nanosized layer of sensing active species (NiOOH) formed on top of Ni(0) working electrode by Ciclic voltammetry experiments in NaOH 0.1M. The species to detect are oxidized at electrode surface by NiOOH forming the Ni(OH)2 species, which is reconverted to NiOOH by application of an external potential (~7V) The sensing mechanism was fully characterized by analytic surface techniques such as X-ray Photoelectron Spectroscopy, Rutherford Backscattering Spectrometry and contact angle measurement. The device exhibited good response towards glucose detection on human blood and saliva samples. It is also suitable for the detection of various analytes such as, aminoacids, alchols and amines on various biological mediums such as human plasma, saliva, and urine. The experiments indicates a strong dependence of the sensitivity from the pH values, in particular the sensitivity increases with the increasing of pH value. For the detection of glucose on blood sample has been found a sensitivity at pH value 11.2 up to 40 μA/mM cm2 with a linear dynamic ranges up to 0–5 mM, while for Saliva sample a dynamic range up to 0-30mM was obtained at pH 13.0. The device shows also good performance for the detection of urinary Phenylalanine level with a good sensitivity of 0.21 μA µM-1 cm-2. The sensing tests for the detection of ethanol report a sensitivity of about 4.23 μM mg l-1 cm-2 for ethanol. A positive sensing response was also proven for the detection of molecules such as amines and diamine (useful markers for food quality), with a limit of detection of about 20 μM. References Petralia, S., Castagna, M. E., Cappello, E., Puntoriero, F., Trovato, E., Gagliano, A. and Conoci, S., Sensing and bio-sensing research 2015, 6, 90–94. S. Petralia, S. Mirabella, V. Strano e S. Conoci, Bionanoscience 7 (2017) 58-63.

Authors : Yassir A. Ali, Ali Uzun, Kasif Teker
Affiliations : Department of Electrical and Electronics Engineering College of Engineering, Istanbul Sehir University, Istanbul, Turkey

Resume : SiC nanowires combine the unique properties of 1D materials with that of intrinsic SiC characteristics and offer great opportunities for UV-sensing applications. SiCNW photoelectric properties have been investigated by exposure at light sources with wavelengths of 254, 365, 532 and 633 nm. The experimental curves have been modelled to exponential rise and decay equations to determine the rise and decay time constants. CVD-grown SiCNW devices have been fabricated through dielectrophoresis onto Au electrodes with a spacing of 3µm onto SiO2/Si. The device was exposed to the 254nm UV light at 2V bias to investigate its photocurrent versus time response with irradiation lasting about 30s. The photocurrent exponentially rises to more than 80% of the saturated current within just under 2s and then reaches to steady value. The decay current took around 3s to fall down to 80% from its maximum value. Moreover, the SiCNW device did not exhibit any persistent photocurrent and showed great reversibility and recovery in photoconductance to the UV exposures. Next, the rise and decay time constants were determined to be 1.3s and 2.35s respectively, as obtained from the representative fitting curves of the photocurrent transients. A very fast photoresponse in both rise and decay processes suggests a small barrier for surface electron-hole recombination. In summary, the quick response of the SiCNW device demonstrates its potential as a photosensor for sensitive applications in photonic devices.

Authors : Xuewei Zhao 1,2,3, Guilei Wang2,3, Jun luo2,3*, Xingxing Ke2,3, Junfeng Li2, WenWu Wang2,3, Chao Zhao2,3, Tianchun Ye2,3 and Henry H. Radamson2,3,4*
Affiliations : 1 University of Science and Technology of China, Hefei 23300, People’s Republic of China 2 Key laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, People’s Republic of China 3 University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China 4 KTH Royal Institute of Technology, Brinellv. 8, 10044 Stockholm, Sweden Email:

Resume : PIN Ge detectors have attracted a large attention due to its detection of telecom wavelength close to 1.5 micrometer. Two major concerns in this type of detector are the dark current and responsivity values. Ge has a lattice mismatch of 4% with Si, therefore a direct growth of Ge material on Si may contain high defect density which can have an impact on the detector’s performance. This article presents and compares three designs where the detectors have been processed on a virtual Ge buffer layer compared to a direct growth on Si. The Ge buffer layer has undergone a cyclic annealing to reduce the defect density in 105 cm-2. The Ge detector structure was grown selectively inside oxide openings formed on a Ge buffer layer or directly on Si substrate. The structures were either selectively grown inside oxide openings or on the entire monitor wafer followed by dry etch to form mesas. In order to remove the residual defects due to dry etch, the mesas went through an ozone treatment and the oxide was removed. The detectors had a cylindrical shape with diameter in the range of 10-100 µm. The top layer of detector was implanted by P to form the n-type layer with concentration of 1x1020 cm-3.  The contact resistance was reduced by forming of NiGe layer prior to the metallization. The metal contacts consisted of a stack of Ti/TiN/AlSi. The Ge epitaxy was carried out at 650 ºC using SiCl2H2 and GeH4 in a reduced pressure chemical vapor deposition system (RPCVD). The performance of detectors was characterized in terms of the responsivity, and dark current. The results showed a minor difference how the detectors have been grown but the contact resistance, defect density and interface quality between the grown structure and the substrate played an important role in the dark current. The dark current was increased with increasing the size of detectors. The best quality PIN structure demonstrated a dark current only a few nA which indicates state-of-art detectors.

Authors : Dawoon Jeong, Minwoo Nam, Doo-Hyun Ko*
Affiliations : Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Korea.

Resume : Luminescent down-shifting (LDS) materials have optical property converting ultra-violet to visible light. We fabricated a transparent luminescent polymer-derived ceramic layer by doping LDS materials such as lanthanide complexes. Moreover, Nano-patterning of the lanthanide-doped ceramic layer enhanced the luminescence compared to reference ceramic layer. This nanostructure has low surface energy, thus enables self-cleaning of substrate. We also realized two-color emission by superimposing physically, so called a “Double imprint”. This technique offers a platform for color-tuning which can present various colors by the combination of two luminescence.

Authors : In-Hwan Ahn, Hyoseong Ahn, Doo-Hyun Ko*
Affiliations : Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, 17104, Korea

Resume : A size modified spherical cavity resonates with the incident light, leading to an increased absorption, which is called whispering gallery mode (WGM). We fabricated a photonic structure doped with spectral conversion materials (such as NaYF4: Yb, Er and quantum dot) using the Langmuir-Blodgett technique. The proposed photonic platform shows the promising result to harness the entire solar spectrum by converting both ultraviolet and near-infrared to visible light by resonant-mode coupling. The overall photoluminescence enhancements exhibit 8.5- and 12.5-fold of upconversion and downshifting luminescence, respectively

Authors : L. Fekete a, L.Volfova a, J. Lancok a, J. Bulir a, J.Chavelier a, M. Klementova a, M. Vrňata b
Affiliations : a Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic b Department of Physics and Measurements, University of Chemistry and Technology Prague, Prague, Czech Republic

Resume : N-type semiconductor nanowires of metal-oxides are promising novel material for gas sensing applications (such as H, S, CO, O2 and others) [1,2]. The concentration of the detected gas dramatically alters electrical conductivity of the nanowire. Large surface-to-volume ratio is an advantage of the nanowires in comparison to 2D coatings. Furthermore, they can be produced on chips in large quantities to enhance the total sensitivity. We will present series of experiments on Sn and Ti thin layers. The metallic layers are grown on fused silica substrates by magnetron sputtering method. For the further experiments we use ultrathin layers with thickness ranging from 5 nm to 20 nm. The metal-oxide nanowires are formed by anodic oxidation using conductive AFM tips. We focus on finding optimal conditions for the preparation of nanowires by varying AFM parameters (applied force, anodic oxidation velocity and applied voltage), initial layer properties thickness and the length of the nanowires. The nanowires are produced in a gap between two platinum electrodes. The electric properties of the nanowires are tested in dependence on their length and gas concentration. Moreover, the nanowires are characterized by SEM-EDS (elemental mapping) to gain their homogeneity and TEM to clarify their nanostructure. [1] Kolmakov A. et al, Adv. Mater. 2003, 15, No.12, 997-1000 [2] Dai Z. R et al, J. Phys. Chem. B 2002, 106, 1274-1279

Authors : Yu.I.Vengryn 1, O.F.Kolomys 2, A.P.Luchechko 3, A.S.Serednytski 1, D.I.Popovych 1,4, V.V.Strelchuk 2
Affiliations : 1.Pidstryhach Institute for Applied Problems of Mechanics and Mathematics NASU. Naukova Str., 3b, Lviv-79060, Ukraine. E-mail: 2. Lashkaryov Institute of Semiconductor Physics of the NAS of Ukraine, Kyiv, Ukraine 3. Electronics and Computer Technologies Department, Ivan Franko National University of Lviv, 50 Dragomanov Street, 79005 Lviv, Ukraine 4. National University “Lvivska Polytechnika”,Bandera strt,12, Lviv-79013, Ukraine.

Resume : The nanopowders (NPs) (ZnO, TiO2) were obtained using the pulsed laser ablation of metallic target (Zn, Ti) in a mixture of reactive (O2) and inert (Ar) gases. The structural and optical properties of the NPs were investigated by X-ray diffractometry, electron microscopy, photoluminescent (PL) and Raman spectroscopy. Studies of the dependence of the intensity of PL of ZnO and TiO2 NPs on the wavelength of excitation including in gases has been carried out and the optimal wavelengths to excitation the visible luminescence are established. On the PL spectra of ZnO NPs, the peak centered at 387 nm with increase in the excitation wavelength from 220 nm to 350 nm, there is a smooth growth of the intensity of the luminescence followed by a sharp increase in its approach to exciton excitation. For other PL band centered at 525 nm when the excitation energy (225<λ<265 (nm)) is much larger than the bandgap there is a smooth increase in the emission intensity. With increasing of the excitation wavelength up to 375 nm, there is a slight decrease in emission and the reveal of sharp peak at 380 nm, which corresponds, apparently, to exciton excitation energies. The next increasing of the excitation wavelength characterized by a sharp decline in PL intensity until its complete quenching at 400 nm. For TiO2 NPs the PL spectra are characterized by an increase in the visible emissions intensity with the excitation wavelength increases from 265 to 405 nm without a noticeable change in the character of the spectrum itself. Based on the phonon bands (mode) analysis in the Raman spectrum of ZnO and TiO2 NPs the character of the quality of the crystal structure are determined and their evolution in the process of laser annealing. The obtained research results were effectively used to increase the selectivity of the gas sensor system by changing the UV excitation wavelength.

Authors : Dejene B.F
Affiliations : Department of Physics, University of the Free State (QwaQwa Campus), Private Bag X13, Phuthaditjhaba, 9866, South Africa.

Resume : Abstract: ZnO nanoparticles were synthesized using sol-gel method. The influence of the annealing temperature on the structural, morphological and optical properties of ZnO nanoparticles is studied. The properties were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), Uv-Vis spectroscopy and EDS. XRD analysis demonstrates that the crystallinity of ZnO is improved with annealing for all growth temperatures selected (45, 55 and 65 °C) as indicated by narrower and more intensified diffraction intensities of the annealed ZnO compared to that of the as prepared particles. The average crystallite sizes of the ZnO particles increased from 29.9 nm to 33.3 nm with annealing indicating the tendency of large grain growth in the nanoparticles due to annealing. SEM micrographs showed that annealed ZnO nanoparticles aggregated and became larger in diameter compared to its as prepared counterparts. The EDS analyses, for as prepared and annealed samples indicate the purity of all the synthesized samples with no peaks other than Zn and O. The photoluminescence peak intensity ratios of ultraviolet to that of visible emission (UVPL/ VisPL) are found to increase on annealing. The UVPL/ VisPL intensities ratio range between 0.9-2.4 for the as prepared samples and 5.0-7.1 for annealed samples. Quenching of visible emission on annealing is known to be responsible for this. The red shift in both the visible and UV emission with increasing particle size due to annealing closely follows the red shift in the band edge emission, indicating that the two complement each other. The average band gap is observed to decrease from 3.25 eV to 3.22 eV with the increase in crystallite sizes occasioned by annealing. Keywords: ZnO; Nanoparticles; Sol-gel; Growth temperature, Structure, Luminescence

Authors : Sabrina Conoci1 ,Francesco Rundo1, Salvatore Petralia1, , Lidia Maddiona1, Emilio Ambra1, Antionio Leonardi2 and Pier Giorgio Fallica1,
Affiliations : 1STMicroelectronics, Str.le Primosole 50, Catania, Italy, 2MATIS CNR-IMM and Dip. of Phys. And Astron. University of Catania, Via S. Sofia 64 Catania, Italy.

Resume : Here we propose an innovative mechanism to detect physiological signals (specifically the PhotoPlethysmoGraphy(PPG) signals) of the driver by means of specific silicon detectors placed on the car steering, composed by a silicon photomultipliers SiPMs having a total area of 4.0x4.5 mm2 and 4871 square microcells with 60 μm pitch coupled in transmission with two OSRAM LT M673 LEDs in SMD package as optical light source. The PPG signal of the driver is reconstructed each time hands are placed on the car steering through the changes on the oxygenated/de-oxygenated hemoglobin captured by the SiPM based sensor. By means of ad-hoc innovative mathematical pipeline based on that nonlinear model, we are able to identify compliant and robust PPG waveforms on the driver PPG signal[1,3]. The described post-processing PPG signal will be performed in a near real-time range compatible with automotive system constraints. Ad-hoc innovative analysis of the post-processed PPG driver signal will be performed in order to establish the driver drowsiness level and, consequently, perform the proper action in order to keep car and driver safety. References [1] F. Rundo, S. Conoci, et al, “PROCESSING OF ELECTROPHYSIOLOGICAL SIGNALS”, IT Patent Nr. 102017000081018, 18 July, 2017; [2] F. Rundo, S. Conoci, et al, “A METHOD OF PROCESSING ELECTROPHYSIOLOGICAL SIGNALS, CORRESPONDING SYSTEM, VEHICLE AND COMPUTER PROGRAM PRODUCT”, IT Patent Nr. 102017000120714, 24 October, 2017; [3] F. Rundo et al “Progresses towards a Processing Pipeline in Photoplethysmogram (PPG) based on SiPMs“, IEEE Proceedings of 23 European Conference on Circuit Theory and Design, Catania(Italy) 4-6 September 2017;

Authors : Salvatore Petraliaa, Maria Eloisa Castagnaa, Francesco Rundoa Antionio Leonardib and Sabrina Conocia.
Affiliations : aSTMicroelectronics Stradale primosole, 50 95121 Catania (Italy) bMATIS CNR-IMM and Dip. of Phys. And Astron. University of Catania, Via S. Sofia 64 Catania, Italy.

Resume : Since the invention of the first Lab-on-Chip system in the 1979, the miniaturization, the ability to move small volume sample into microstructures and to perform biological reaction have become indispensable for molecular diagnostics and sensing applications. Here is described a miniaturized system composed by a silicon microchip able to electrically deliver a sample volume of 20µl of liquid into miniaturized 96 silicon microchambers 200nl each in volume. The device contains also integrated temperature sensors and heaters for thermal driving. The silicon microchambers are chemically treated by a specific surface chemistry to permit the liquid movement. The coating was properly engineered to permit the switching from hydrophobic surface with a static contact angle value of about 110°, to hydrophilic surface with a static contact angle value less than 5°, by an external electrical filed application. An electrical conductive polycarbonate structure was properly engineered to permit the external electric field application. The entire hybrid structure (polycarbonate and silicon chip) is connected to a circuit board that drives the chip through a specific software that is also able to analysed the collected data. A CCD camera is also embedded to monitor the liquid movement. Thanks to the integrated silicon temperature sensor and heaters, the chip allows a temperature control accuracy of ± 0.2 °C, heating rate of 15 °C/s and cooling rate of 8 °C/s. This system very appealing for gene expression applications in miniaturized PCR lab-on-a-chip, where both very small volume (about 20uL) and high number of chambers (>100) are required.

Authors : Salvatore Petralia1, Maria Grazia Amore1, Emanuele Luigi Sciuto2, Antonio Leonardi2 Salvatore Abbisso1, Roberta Giuffrida1, Giuseppe Tosto1 and Sabrina Conoci1,
Affiliations : 1STMicroelectronics, Stradale Primosole, 50 – 95121 Catania, Italy 2 Department of Phys. And Astron. University of Catania, Via S. Sofia 64 Catania, Italy.

Resume : The miniaturization of device able to perform nucleic acid detection by Real time PCR method is a key point to develop the“genetic point-of-care” system for sample-in-answer-out analysis. In this scenario an innovative Lab-on-Disk system was developed for the detection of pathogen nucleic acids (DNA). The miniaturized system is composed by a hybrid silicon-polycarbonate chip with six OR 12 microchambers, embedded on a polycarbonate holder with four chip position and a reader for the real time PCR thermocycling experiments. The hybrid silicon-polycarbonate device manufactured by standard semiconductor technology integrates in the silicon part the heaters and temperature control sensors to perform thermal cycles with an accuracy of 0.1 °C, the polycarbonate part is glued with silicon part to form the microchambers. A customized and easy-to-use reader integrates an electronic board to driven the silicon device and the optical module for RT-PCR fluorescence images acquisition. Two different wavelength (FAM and VIC) are available. This work reports the experimental results for the detection of Hepatitis Viruses B (HBV) genome. The results indicate an good improvement of sensitivity ( about 1 cycle threshold) respect to the commercial RT-PCR platforms. This improvement is an important features for application on infectious disease where the amount of pathogen genome is very low. This straightforward improvement on sensitivity is mainly due to the particular microchambers shape and reader performance. References S. Petralia, and Sabrina Conoci. ACS Sensors. 2017, 2, 876. S. Petralia, M. E. Castagna, M. O Spata, M. G. Amore and S. Conoci Biosens J, 2016, 5:1 S. Petralia, E. L. Sciuto, M. L. Di Pietro, M. Zimbone, M. G. Grimaldi and S. Conoci. Analyst, 2017, 42, 2090.

Authors : I.Guizani, W.Q. Jemmali, M.M. Habchi, A. Rebey
Affiliations : University of Monastir, Faculty of Sciences, Unité de Recherche sur les Hétéro-Epitaxies et Applications, 5019 Monastir, Tunisia

Resume : We have theoretically investigated the 1.55 µm p-i-n GaNAsBi-based multiple quantum wells (MQWs) using a self-consistent calculation combined with 16x16 BAC model. Their performances are evaluated in terms of optical gain and radiative current density J_rad. We have found that J_rad reduces by increasing the well thickness〖 L〗_ω. The quantum confined Stark effect as well as the doping effect on spontaneous emission and radiative current density in ideal lasers are also discussed. The optical properties of the heterostructure are improved when the MQWs are doped. The optimization of well parameters can be used as a basis for GaNAsBi-based lasers intended for optical fiber telecommunication wavelength.

Authors : Maria Josè Lo Faro1,2, Antonio Alessio Leonardi1,2,3,4, Barbara Fazio2, Francesco Priolo1,3,5, Alessia Irrera2, Maria Miritello1
Affiliations : 1 MATIS CNR-IMM Sede Università, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania, Italy; 2 CNR-IPCF, Istituto per i Processi Chimico-Fisici, V.le F. Stagno D’Alcontres 37, 98158 Messina, Italy; 3 Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 4 INFN sezione di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 5 Scuola Superiore di Catania, Via Valdisavoia 9, 95123 Catania, Italy;

Resume : Silicon physical properties, easy manufacturing and cheapness promoted its industrial employment as a leading material for different applications. Si indirect bandgap is a great limit for photonics and the scientific community has devoted efforts on the realization of a new class of efficient light emitters based on Si platforms. By a low cost and industrially compatible method, we realized ultrathin and dense vertical array of Si nanowires (NW) that efficiently emit light in the visible at RT due to quantum confinement. Fractal arrays of Si NWs exhibiting a strong light trapping from visible to near-IR were synthesized without any lithography or mask. We engineered the realization of multi-wavelength light sources operating at RT by decorating fractal Si NW with Er doped yttrium oxide deposited by sputtering in oblique angle deposition configuration by placing the substrate at different angles with respect to the normal direction to the target. Er in yttrium oxide is characterized by intense IR emission strategic for telecom applications. The structural properties and fractal parameters were characterized as a function of deposition settings and correlated to the optical properties. By using different excitation wavelengths, we demonstrate the Er emission is enhanced by scattering effect driven by the fractal morphology of the NW array. This material opens new perspectives for Si platform as active medium in light sources for Si photonics and telecommunication applications.

Authors : J. Costa, H. Vieira, P. Louro, M. Vieira
Affiliations : ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Portugal CTS-UNINOVA, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal.

Resume : Photopletysmography (PPG) is a very common optical approach to measure blood oxygen levels for patient monitoring as well as heart rate in fitness tracking devices. In the transmission mode the use of amorphous silicon photodiodes falls short of other solutions because the light sources are selected in the red and near infrared region of the spectrum, where the sensitivity of photodiodes is limited, to obtain better transmission through human tissue. Nevertheless, a number of studies have shown that reflection mode PPG using visible light is also an interesting option due to the reduction of motion artifacts, which can be critical in sports applications and portable medical devices. In this region of the spectrum an amorphous silicon photodiode provides an interesting solution due to its sensitivity and low fabrication cost using Plasma Enhanced Chemical Vapor Deposition (PECVD) In this study we use a double junction amorphous silicon photodiode for PPG in the reflection mode. The active device is a double photodetector produced by PECVD. It consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructure with high resistivity doped layers packed between two transparent oxide layers (TCO) made of ITO. The energy gap and semiconductor properties of each junction have been selected to provide sensitivity across the visible range. The photodiode can be electrically biased to tune for different wavelengths. This can be of particular interest for PPG where there is a trend towards increasing the number of wavelengths using multiple LEDs not only to improve the accuracy of SpO2 measurements, but also to provide real-time measurements of other substances in blood. We describe the physical and optical characteristics of the photodiode that make it useful for this application and have developed a test prototype to assess it, which includes the LED control system and the signal conditioning circuit for acquisition of the PPG signals. The results allows to define wavelengths of interest taking in consideration the sensitivity of the photodiode and regions of operation in terms of switching frequency of the LEDs.

Authors : Dana Cristea, Paula Obreja, Roxana Tomescu
Affiliations : National Institute for R&D in Microtechnologies, IMT Bucharest

Resume : In this paper we present an improved architecture for silicon plasmonic hot electron detector with high responsivity in the SWIR range. Hot electron devices consist typically of a metal surface in contact with a semiconductor forming a Schottky barrier. Hot electrons generated in the metal layer from the nonradiative decay of surface plasmons (SPs) can be emitted (internal photoemission process- IPE) over the barrier into the semiconductor if their energy is higher than the Schottky barrier. IPE enables sub-bandgap photodetection making thus silicon devices suitable for operation in the NIR-SWIR ranges. However the efficiency of IPE process is low due to the momentum mismatch between the bound surface plasmon and the free propagating incoming photons. To allows incident light to be momentum matched and efficiently coupled to SPs we used corrugated electrodes. We developed a simple process for the fabrication of plasmonic corrugated structures without using costly and time-consuming nano-lithographic processes. The process is based on vacuum deposition of very thin Ag layer followed by thermal annealing. A periodic structure composed of flattened nano-hemispheres is obtained. The diameter and the high of the nanostructures depend on the initial thickness of the Ag layer and on the annealing process parameters. The corrugated Ag layer acts as metamaterial absorber that improves the efficiency of hot electrons generations. The devices show very high resposivities, up to 12 mA/W at 1550 nm, among the highest reported. The device bandwidth can be tuned by modifying the geometry of the metamaterial. Acknowledgments: The work was supported by a grant of the Romanian Ministry of Research and Innovation, project PN-III-P2-2.1-PED-2016-0307.

Authors : Afef Ben Mansour, Adnen Melliti, Asmaa Sahli, Radhouane Chtourou
Affiliations : National Higher Engineering School of Tunis; National Higher Engineering School of Tunis; IBN Rochd University Hospital Center; Tunis Center for Research and Energy Technologies

Resume : The optical properties of InAs quantum dots with two different strain-reducing layers (SRLs) were characterized using photoluminescence (PL). The used SRLs are GaAs1−xSbx(x=6%) and InyGa1−yAs1−xSbx (x=1.2%, y=14%). A longer emission wavelength with InAs/InGaAsSb QDs has been identified. It reaches 1406 nm and 1340 nm for ground and first excited state at room temperature, favoring the application of the ES quantum dot laser in optical-fiber communications. Variation of PL peak energies and full width at half maximum of the QDs ground state transition as a function of excitation density were studied. Dependence of the integrated PL intensity as a function of the excitation density at different temperatures was also studied. For low temperature and low excitation density, the integrated PL intensity increases nearly linearly with excitation (slope is slightly lower than unity) in all samples. This linear dependence is typical for localized excitons. Further, the increase of the excitation power density results in a superlinear dependence (slope is between 1 and 2). Indeed, the increase of the excitation power at low temperature favors the filling of the localized states and allows the excitons to recombine non-radiatively. With increasing temperature, superlinear dependence is conserved and even increased slightly. This behavior is explained by the thermal energy which becomes comparable to the binding energy of excitons that can be dissociated and recombine as free carriers.

Authors : Antonio A Leonardi1,2,3, Maria j Lo Faro1, Fabio Iacona2, Paolo Musumeci3, Barbara Fazio1, Francesco Priolo2,3,4
Affiliations : 1 IPCF—CNR, V.le F. Stagno d’Alcontres 37, I-98156 Messina, Italy 2MATIS IMM—CNR, Via Santa Sofia 64, I-95123 Catania, Italy 3 Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, I-95123 Catania, Italy 4 Scuola Superiore di Catania, Via Valdisavoia 9, I-95123 Catania, Italy

Resume : Semiconductor NWs have been proven to be useful as basic building blocks for photonic components, including lasers, detectors, modulators and solar cells. Silicon is the most important semiconductor and the possibility to obtain an efficient room temperature light emission from Si NWs would represent an important advancement in photonics. In spite of this great potential interest, light emission from Si NWs is still a scarcely reported and unexplained phenomenon. We will present a new approach for Si NWs synthesis, based on a metal-assisted wet etching process. The process is simple, cheap, fast, compatible with Si technology and, above all, able to synthesize Si NWs exhibiting a strong room temperature photoluminescence (PL). We will present a detailed analysis of the steady-state and time-resolved PL properties of the system as a function of aging, temperature and pump power to demonstrate that the emission is due to the occurrence of quantum confinement effects. Moreover, we will present a prototype device based on Si NWs exhibiting a strong and stable room temperature electroluminescence at operating voltages as low as 2 V. These results open the route towards novel photonic applications of silicon NWs as efficient light sources.

Authors : R.A. Picca1, A. A. Leonardi2,5, M.J. Lo Faro2, C.D. Calvano1, B. Fazio2, S. Trusso2, P.M. Ossi3, F. Neri4, C. D’Andrea5, N. Cioffi1
Affiliations : 1Dipartimento di Chimica, Università degli Studi di Bari “Aldo Moro”, Via E. Orabona, 4 – 70126 Bari 2IPCF-CNR, viale F. Stagno d’Alcontres 37, Faro Superiore, 98158 Messina 3Dipartimento di Energia & Center for NanoEngineered Materials and Surfaces-NEMAS, Politecnico di Milano, Via Ponzio, 34-3, 20133 Milan, Italy 4Dipartimento di Fisica e di Scienze della Terra, Università di Messina, V.le F. Stagno d’Alcontres 31, 98166 Messina, Italy 5MATIS IMM CNR e Dipartimento di Fisica, Università degli Studi di Catania, Via Santa Sofia 64, 95123 Catania

Resume : Nowadays, nanomaterials are widely employed as substrates in laser desorption/ionization mass spectrometry (LDI-MS) analysis of small molecules [1]. Among different materials, silicon nanowires (SiNWs) are recognized as efficient substrates thanks to the reduction of background interference below 1000 m/z, at low laser fluence [2]. Here, we report on the successful LDI-MS application of SiNWs prepared by a mask-less wet-etching protocol at room temperature followed by their decoration with silver nanoparticles (AgNPs), produced by pulsed laser deposition. Such hybrid systems (AgNPs@SiNWs) are extremely active substrates, especially towards analytes bearing unsaturated bonds. Free fatty acids in vegetable oils can be investigated through this approach without severe sample pretreatment [3]. Moreover, surface chemical characterization confirmed that nanostructured Ag(0) was present on the surface. [1] R.A. Picca et al., Nanomaterials 7 (2017) 75, doi:10.3390/nano7040075. [2] M. Dupré et al., Analytical Chemistry 84 (2012) 10637. [3] R.A. Picca et al., Journal of Mass Spectrometry 51 (2016) 849.

Authors : Maria J Lo Faro1,2, Antonio A Leonardi1,2,3, Cristiano D’Andrea1, Paolo M Ossi4, Fortunato Neri5, Paolo Musumeci3, Nicola Cioffi7, Francesco Priolo1,3,8 Barbara Fazio1, Sebastiano Trusso1.
Affiliations : 1 IPCF—CNR, V.le F. Stagno d’Alcontres 37, I-98156 Messina, Italy 2MATIS IMM—CNR, Via Santa Sofia 64, I-95123 Catania, Italy 3 Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, I-95123 Catania, Italy 4 Dipartimento di Energia, Center for Nanoengineered Materials and Surfaces-NEMAS, Politecnico di Milano, via Ponzio 34-3, I-20133 Milano, Italy 5 Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e della Terra, Università di Messina, V.le F. Stagno d’Alcontres, 31, 98166, Messina, Italy 6 Dipartimento di Fisica, Università degli Studi di Pavia, via Bassi 6, 27100 Pavia, Italy 7 Dipartimento di Chimica, Università degli Studi Bari ‘Aldo Moro’, Via E. Orabona 4, 70126 Bari, Italy 8 Scuola Superiore di Catania, Via Valdisavoia 9, I-95123 Catania, Italy

Resume : The high aspect ratio of Si nanowire (NW) arrays has a great potential for many applications and in particular for Si-based sensors. For this purpose, we coupled the huge surface-to-volume ratio of Si NW to plasmonic effects decorating the NW array with metal nanoparticles (NPs). Si NWs were synthesized by metal-assisted chemical etching and then decorated with silver nanoparticles (NPs) produced by pulsed laser deposition (PLD). Both NW synthesis and decoration techniques are performed at room temperature with a low-cost and Si implementable technology. The obtained Ag NP decorated Si NWs are free from chemicals contamination and there is no need of post deposition high temperature processes. The results show that this approach allows the full coverage of the Si NW walls with a strong control on the Ag NP size and distribution. The optical properties of Si NW arrays were investigated by reflectance spectroscopy showing the presence of a plasmon absorption peak dependent on the Ag NP morphology. The great potentialities of PLD metal decoration of Si NWs for surface enhanced Raman spectroscopy (SERS) applications are reported as a function of rhodamine 6G (R6G) concentration in aqueous solution. A very low limit of detection of 10−8 M was demonstrated and a SERS enhancement factor of 108 of about one order of magnitude higher with respect to a similarly decorated Si flat surface was estimated.

Authors : M.J. Lo Faro1,2, A.A. Leonardi1,2,3,4, C. D’Andrea1, B. Fazio1, P. Musumeci4, C.Vasi1, F. Iacona2, F. Priolo4,7,
Affiliations : 1 CNR-IPCF, Istituto per i Processi Chimico-Fisici, V.le F. Stagno D’Alcontres 37, 98158 Messina, Italy; 2MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania, Italy; 3 INFN sezione di Catania, Via Santa Sofia 64, 95123 Catania, Italy; 4Dipartimento di Fisica ed Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy;; 7 Scuola Superiore di Catania, Via Valdisavoia 9, 95123 Catania, Italy;

Resume : Si-based multiwavelength light sources are of great interest for applications in photonics and multiplexed signal communication. The realization of an innovative hybrid light source operating at room temperature, obtained by embedding a carbon nanotube (CNT) dispersion inside a Si nanowire (NW) array is reported. Ultrathin Si nanowires (NWs) synthesized by metal assisted chemical wet etching using a very thin discontinuous Au layer as precursor were used as platform and coated with debundled single walled carbon nanotube (CNT) dispersions. A bright room temperature emission in the visible range due to electron–hole recombination in quantum confined Si NWs is reported. The hybrid Si NW/CNT system exhibits a room temperature simultaneous emission both in the visible (due to Si NWs) and the IR (due to CNTs) ranges, thus demonstrating the realization of a low-cost material with promising perspectives for applications in Si-based photonics. The detailed study of the optical properties of the hybrid system evidences that the ratio between the intensity of the visible and the IR emissions can be varied within a wide range by changing the excitation wavelength or the CNT concentration and the conditions leading to the prevalence of one signal with respect to the other were investigated. The multiplicity of emission spectra obtainable from this composite material opens new perspectives for Si nanostructures as active medium in light sources for Si photonics applications.

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Session 9: Innovative materials and characterizations : W. Skorupa, H.H. Radamson
Authors : Steven Koester
Affiliations : Department of Electrical and Computer Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455

Resume : Two-dimensional (2D) materials, layered crystals with strong intra-layer covalent bonds and weak inter-layer van der Waals coupling, have been of great interest recently within the scientific community. While 2D materials possess many unique properties, it remains an open question for which applications these materials can truly provide a benefit compared to conventional solutions. Here, I describe our work on 2D materials, and discuss potential applications in electronics, sensing and spintronics where these materials have the potential to provide improved and/or novel functionality compared to the state of the art. Graphene, a single sheet of sp2-bonded carbon has extremely high mobility, but its zero-gap band structure makes it poorly suited for conventional field-effect transistors. Instead we have shown that numerous other properties of graphene can be utilized to create new types of devices. For instance, we have shown that the quantum capacitance in graphene can be utilized to realize variable capacitor (varactor) sensors [1,2]. These sensors have the potential for small size, multiplexed sensing capability, and most importantly, wireless readout capability [3]. More recently, we have shown that graphene edges can form atomically sharp “tweezers” for trapping biomolecules such as DNA [4]. Due to the atomic-scale sharpness of graphene, this trapping can occur at extremely low voltages (as low as 700 mV), making them suitable for integration with on-chip electronic reado

Authors : J. Cardin(1), L. Dumont(1), F. Ehré(1), C. Labbé(1), C. Dufour(1), P.-M. Anglade(1), M. Vallet(2), M. Carrada(2), I.-S. Yu(3), F. Gourbilleau(1)
Affiliations : (1) CIMAP, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, 6 Boulevard Maréchal Juin 14050 Caen Cedex 4, France (2) CEMES/CNRS, Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse Cedex 4, France (3) Department of Materials Science and Engineering, National Dong Hwa University, No. 1, Sec. 2, Da Hsueh Rd. Shoufeng , Hualien 97401, Taiwan, R.O.C

Resume : Among many innovative approaches proposed to increase the silicon Solar Cell (Si-SC) efficiency, the frequency conversion layer which spectrally redistributes the irradiance from either direct sun light in case of Down Conversion (DC) or Down Shifting (DS) layers or from transmitted and back reflected light in case of Up-Conversion (UC) layer is promising. Thus, frequency conversions may increase SC efficiency at the expense of the thermalization of generated carriers due to the improved spectral overlapping between the irradiance and the Si-SC absorptivity. Those mechanisms are often based on absorption and emission of trivalent Rare Earth (RE) ions. Thus for DC process couples of ions such as Tb3 (Pr3 )-Yb3 are used while for the DS one, ion such as Pr3 or Tb3 has been tested. Unfortunately, RE ions major drawbacks are their low excitability by solar irradiance and chemical incompatibility of usual host matrix with Si-SC process. The purpose of this paper is to present the fabrication and study of DC (DS) homogenous and superlattice layers which consist in a Si-based matrix doped with Tb3 (Pr3 )-Yb3 ions fabricated by a co-sputtering approach. High conversion efficiency DC (DS) layers were structurally and optically characterized. Modelling by means of Monte Carlo approach and by rate equations model allowed us to better understand the role of RE ions interdistances on the energy transfer mechanism and consequently on the efficiency of the frequency conversion.

Authors : Søren Roesgaard (1), Lichun Meng (2), Peter Tidemand-Lichtenberg (2), Jeppe Seidelin Dam (2), Peter John Rodrigo (2), Christian Pedersen (2), and Brian Julsgaard (1,3).
Affiliations : (1) Interdisciplinary Nanoscience Center (iNano), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark; (2) DTU Fotonik, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde, Denmark; (3) Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Dk-8000 Aarhus C, Denmark.

Resume : Time-resolved photoluminescence spectroscopy is a powerful tool for examining the dynamics of optically active materials. At the standard fiber communication wavelengths of 1.5 microns such experiments can be carried out using commercial InP/InGaAs photomultiplier tubes. However, at longer wavelengths, relevant for e.g. the recent developments within GeSn laser materials, other techniques must be employed. Here we report on our work using non-linear optics for upconverting long-wavelength photoluminescence into short-wavelength light detectable by standard silicon-based detectors with nanosecond time resolution.

Authors : Chih-Jen Shih; Jakub Jagielski; Sudhir Kumar
Affiliations : Institute for Chemical and Bioengineering, ETH Zurich

Resume : The outstanding excitonic properties, including photoluminescence quantum yield (PLQY), of individual, quantum-confined semiconductor nanoparticles are often significantly quenched upon aggregation, representing the main obstacle towards scalable photonic devices. Here we report aggregation-induced emission (AIE) phenomena in the lamellar solids containing layer-controlled colloidal quantum wells (CQWs) of hybrid organic-inorganic lead bromide perovskites, resulting in anomalously high solid-state PLQY of up to 94%. Upon forming the QW solids, we observe an inverse correlation between exciton lifetime and , clearly distinct from that in typical quantum dot solid systems. Our multiscale theoretical analysis reveals that in a lamellar solid, the collective motion of the surface organic cations are more restricted to orient along the [100] direction, thereby inducing a more direct bandgap that facilitates radiative recombination. Using the QW solids, we demonstrate ultra-pure green emission by completely downconverting a blue GaN light emitting diode (LED) at room temperature, with a luminous efficacy higher than 90 lm/W at 5,000 cd/m2, which has never been reached in any nanomaterial assemblies by far.

Authors : L.Arnoldi*, M.Borz*, I.Blum*, A.Obraztsov**, A.Vella*
Affiliations : *Groupe de Physique des Matériaux UMR CNRS 6634, Université et INSA de ROUEN, Université Normandie 76801 SAINT ETIENNE DU ROUVRAY CEDEX France ** University of Eastern Finland, Department of Physics and Mathematics, Joensuu 80101, Finland ** M. V. Lomonosov Moscow State University Department of Physics, Moscow 119991, Russia

Resume : Mono-crystalline diamond needles are quite attractive samples for field emission applications, mainly used as point electron source. The performances of these electrons sources change from one needle to another. These changes could be related to a variation in the electrical conduction therefore we used a new experimental setup to study the conduction properties of diamond nano-needles in a large range of emission currents and under femtosecond laser illumination. The experimental setup is a field ion microscopy (FIM), equipped with an energy analyzer and a amperemeter, used to measure the emitted ion current at the needle apex and the energy of these emitted ions. Changing the voltage applied to the nanoneedle, we exhibited two different conduction behaviors: a first regime, at low emission current, which corresponds to the ohmic conduction and a second regime, at high emission current, which corresponds to a Poole-Frenkel (PF) conduction mechanism. We discuss the transition between these two conduction mechanisms and its dependence as a function of the emitted current and the needle geometry. Under femtosecond laser illumination, the resistivity changes and the transition from the ohmic conduction regime to the PF regime is observed at higher emission currents. The study of the changes of the conduction parameters under illuminations allows us to draw conclusion on the optical absorption process of these nanoneedles and on their heating induced by laser illumination.

Authors : Xue Feng, and Yidong Huang
Affiliations : Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing 100084, China

Resume : Introduced by Allen et al., it has been realized that light can carry orbital angular momentum (OAM) in addition to the spin angular momentum (SAM). Independent of the polarization state, light with an azimuthal phase dependence of exp(ilφ) has OAM lћ per photon. The value of l (the topological charge), as a new dimensionality, can be valued with any integer. Having l spiral phase fronts and a transverse component of the Poynting vector perpendicular to the propagating direction, such kind of light is also known as optical vortex. Aim to explore the benefit introduced by optical vortex, we have proposed and demonstrated several photonic integrated devices. In this article, some representative devices of our recent work would be briefly introduced. They are the integrated “Cobweb” emitter with a wide switching range of OAM modes, integrated “Cogwheel” emitter to generate optical superimposed vortex beam and plasmonic vortex devices. (1) Integrated “Cobweb” emitter with a wide switching range of OAM modes. The independence of the micro-ring cavity and the gratings unit provides the flexibility to design the device and optimize the performance. Specifically, the dynamic switching of 9 OAM modes (l = –4~4) with azimuthal polarization has been demonstrated with electrically controlled thermo-optical effect (Scientific Reports 6: 22512, (2016)). (2) Integrated “Cogwheel” emitter to generate optical superimposed vortex beam with tunable OAM. With fixed wavelength and power of incident beam, the OAM of the radiated optical superimposed vortex beam can be dynamically tuned. The experimental results confirm the tunability of superimposed vortex beams with topological charge of l=-5~5. (3) Plasmonic vortex devices: As a fundamental tool for light-matter interactions, plasmonic vortex (PV) is extremely attractive due to its unique near field properties. However, it is hard to dynamically and continuously tune the OAM carried by PVs and the properties of fractional PVs are still not well investigated. We have proposed a novel method of utilizing the propagation induced radial phase gradient of incident Laguerre-Gaussian (LG) beam to sculpture PVs from integer to fractional OAM dynamically. Furthermore, a series of plasmonic devices are proposed to generate multi-patterned and two-dimensional optical lattice with helicity or not. Due to spin-orbit coupling, both the spin and orbital angular momentum of incident beam as well as the excited polygonal plasmonic mode contribute to the formation of optical lattice. With the compactness and flexible tunability, we believe that this work would facilitate the utilization of optical lattice in various on-chip applications.

Authors : M. Fukuda, M. Ota, K. Nakayama, S. Higuchi, T. Furuki, R. Watanabe, Y. Kikuchi, Y. Tonooka, T. Hirano, T. Inoue, and Yuya Ishii
Affiliations : Toyohashi University of Technology

Resume : Performances of silicon integrated circuits (ICs) are limited by wire delay and power consumption, but might be improved by the introduction of optical techniques. Combining plasmonic circuits with silicon ICs is one solution; however, surface plasmon signals suffer from larger transmission losses than electrical and optical signals. Here, we discuss the applicability of plasmonic ICs to silicon substrates in terms of energy loss and transmission speed. The signal transmission speed in plasmonic ICs, which is determined by the circuit dispersion, was about two-orders of magnitude higher than that of electrical ones determined by circuit capacitance and resistance. We compared the transmission energy losses in plasmonic waveguides and electric wirings and clarified that plasmon signals are superior to electric signals if suitable waveguide structures are selected and the area of the circuit is within a few hundreds of micrometers. We developed various plasmonic components, based on CMOS-compatible processes, for merging with silicon ICs. These components consist only of materials used in silicon ICs. Plasmonic signals were transmitted, modulated, used for logic operation, and detected in the circuits without any additional components. The scales of each component were of less than a few tens of micrometers, and these results suggest promise for the integration of plasmonic components into silicon ICs.

Authors : A.S. Mehra1, H. Choudhary1, S.K. Srivastava1, Vandana1, R. Srivastava1, C.M.S Rauthan1, Rana Biswas2, P. Prathap1
Affiliations : 1Inorganic Photovoltaic Devices Group, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi-110012, India 2Ames Laboratory; Microelectronics Research Center; Department of Physics & Astronomy; Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA

Resume : Light management and surface passivation has become an important aspect to improve the performance of solar cells, particularly based on thinner wafers and foils. Hence, we develop unique three-dimensional (3-D) dielectric photonic (nanocones and gratings) structures (PS) in SiO2 layers that efficiently trap light in silicon cells. The PS were designed using simulations. The PS of SiO2 were developed using nanoimprint lithography based on commercial silica gel layer. The nanostructures showed a high optical transmittance of > 95 %. The aspect ratio of PS varied with the processing conditions and grating showed a height profile of 450 nm while it is ~200 nm for cones. The PS showed a minimum reflectance of 15 % in the visible wavelength range. The as-deposited dielectric PS on n-type silicon showed considerable passivation and its quality improved to a minority carrier lifetime of 287 s at an injection level, 10E15 cm-3 after a short annealing in forming gas. The study demonstrates a promising approach for designing a variety of photovoltaic devices, particularly flexible crystalline silicon solar cells.

Authors : M. Vieira (1,2,3), M. A. Vieira(1,2), P. Louro(1,2), P. Vieira (1,4)
Affiliations : 1Electronics Telecommunication and Computer Dept. ISEL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal 2 CTS-UNINOVA, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal. 3 DEE-FCT-UNL, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal. 4 Instituto de Telecomunicações, Instituto Superior Técnico, 1049-001, Lisboa, Portugal

Resume : A VLC indoor positioning system that uses white RGB-LEDs for both illuminations proposes and as data transmitters is presented. The receiver is implemented using a double p-i-n/pin SiC photodetector with light filtering properties. An OOK modulation scheme is used to modulate the light. Optoelectronic characterization of the transmitter and receiver are performed. A detailed analysis of the component’s characteristics within the VLC system, such as multiplexing techniques, visible light sensing, indoor localization and navigation recognition were discussed. LED bulbs work as transmitters, sending information together with different identifiers, IDs, related to their physical locations. Square and hexagonal topologies for the unit cell are tested, and a 2D network localization design, demonstrated by a prototype implementation, is presented. The key differences between both topologies are discussed. Fine-grained indoor localization is tested. The received signal is used in coded multiplexing techniques for supporting communications and navigation concomitantly on the same channel. The position of the device is estimated by measuring the strength of the MUX signal from several transmitters. The location and motion information is calculated by position mapping and estimating the location areas. For both topologies, the transmitted data information, indoor position and motion direction of the mobile device are determined.

Authors : P. Louro1,2, M. Vieira1,2,3, J. Costa1,2, M. A. Vieira1,2
Affiliations : 1. ISEL-IPL, R. Conselheiro Emídio Navarro, 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, ; 2 CTS-UNINOVA, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal. 3 DEE-FCT-UNL, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal

Resume : White LEDS revolutionized the field of illumination technology mainly due to the energy saving effects. Besides lighting purposes LEDs can also be used in wireless communication when integrated in Visible Light Communication (VLC) systems. Indoor positioning for navigation in large buildings is currently under research to overcome the difficulties associated with the use of GPS in such environments. In this work it is proposed an indoor navigation system based on the use of VLC technology. The proposed system includes tri-chromatic white LEDs with the red and blue chips modulated at different frequencies and a pinpin photodetector with selective spectral sensitivity. Optoelectronic features of both optical sources and photodetector device are analyzed. The photodetector device consists two pin structures based on a-SiC:H and a-Si:H with geometrical configuration optimized for the detection of short and large wavelengths in the visible range. Its sensitivity is externally tuned by steady state optical bias. The localization algorithm makes use of the Fourier transform to identify the frequencies present in the photocurrent signal and the wavelength filtering properties of the sensor under front and back optical bias to detect the existing red and blue signals. The viability of the system was demonstrated through the implementation of an automatic algorithm to infer the photodetector cardinal direction.

Session 10: Material engineering for electronics and photonics : A. Irrera
Authors : Shujuan Mao, Guilei Wang, Jing Xu, Dan Zhang, Ningyuan Duan, Shi Liu, Wenwu Wang, Dapeng Chen, Junfeng Li, Chao Zhao, Tianchun Ye and Jun Luo
Affiliations : The institute of Microelectronics, Chinese Academy of Sciences (IMECAS)

Resume : In this work, the impact of different Ge PAI on the formation of ultrathin TiSix films as well as on the specific contact resistivity in TiSix/n-Si contacts were investigated systematically. Extensive material characterizations such as cross-sectional transmission electron microscopy (XTEM), X-ray diffraction (XRD) and angle-resolved X-ray photoelectron spectroscopy (ARXPS), as well as electrical characterizations such contact resistivity values, Schottky barrier height (SBH) and leakage current of p-n junctions, were performed. It is found that Ge PAI indeed promotes the Ti silicidation at 550 oC and the resultant tTiSix values are strongly dependent on the thickness of amorphous Si (t-Si) created by Ge PAI. The stoichiometry of TiSix films is rather graded than constant from the TiN/Ti side to Si side. Proper Ge PAI is beneficial in reducing the c values in TiSix/n-Si contacts and this reduction in c cannot attributed to the reduction of SBH. Though proper Ge PAI leads to reduced c values, the leakage current of p-n diodes is increased as a penalty which needs to be compromised in practical applications.

Authors : Taige Dong,1 Zhimin Zhu,1 Sun Ying,1 Junzhuan Wang,1 Linwei Yu *,1,2 Jun Xu1 and Pere Roca i Cabarrocas 2
Affiliations : 1 National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering, Nanjing University, 210093 Nanjing, P. R. China 2 LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France

Resume : The modern electronics have been built upon the solid basis of bulk crystalline silicon (c-Si), which is, however, a brittle semicondutor that has little stretchability. So far, most of the stretchable electronics have been prototyped and fabricated with polymer and organic semiconductors, which usually offers poorer electronic characteristics compared to those of c-Si based devices, particularly in terms of carrier mobility, passivation and stability in air/humidity exposure. In order to extend the legend of c-Si into the emerging application of soft electronics or bio-sensors applications, line-shape engineering has been a key strategy to endow extra flexibility and stretchability to quasi-1D silicon nanowires (SiNWs) channels. We here explore a self-assembly in-plane solid-liquid-solid (IPSLS) growth of SiNWs,[1-4] where a thin film of amorphous Si (a-Si) is fed as precursor layer to drive the indium (In) or tin (Sn) nano-droplets to move and produce well-defined crystalline SiNWs behind. The line-shape of the in-plane SiNWs can be engineered either via a self-automated zigzag growth, stimulated by a strong interface squeezing interaction during the in-plane growth,[5] or via a deterministic line-shape programming of in-plane SiNWs into extremely stretchable springs or arbitrary 2D patterns, with the aid of a precise guided growth along programmed step edges.[6] A reliable and faithful single run growth of c-SiNWs over turning tracks with different local curvatures has been well established, while high resolution transmission electron microscopy analysis reveals a high quality mono-like crystallinity in the line-shaped engineered SiNW springs. Excitingly, in situ scanning electron microscopy stretching and current-voltage characterizations also demonstrate a super-elastic and robust electric transport carried by the SiNW springs even under large stretching of more than 200%. This highly reliable line-shape programming approach holds a strong promise to employ the mature c-Si technology for the development of a new generation of high performance bio-friendly and stretchable electronics. As an example, we will also demonstrate a highly stretchable networks of continuous c-Si springs and explore their applications for bio-sensing on curvilinear human skin or tissue surface. References [1] L. Yu, P.-J. Alet, G. Picardi, P. Roca i Cabarrocas, Phys. Rev. Lett. 2009, 102, 125501. [2] L. Yu, P. Roca i Cabarrocas, Phys. Rev. B 2010, 81, 085323. [3] M. Xu, Z. Xue, J. Wang, Y. Zhao, Y. Duan, G. Zhu, L. Yu, J. Xu, J. Wang, Y. Shi, C. Kunji, P. Roca i Cabarrocas, Nano Lett. 2016, 16, 7317. [4] Z. Xue, M. Xu, Y. Zhao, J. Wang, X. Jiang, L. Yu, J. Wang, J. Xu, Y. Shi, K. Chen, P. Roca i Cabarrocas, Nature communications 2016, 7, 12836. [5] Z. Xue, M. Xu, X. Li, J. Wang, X. Jiang, X. Wei, L. Yu, Q. Chen, J. Wang, J. Xu, K. Chen, P. Roca i Cabarrocas, Adv. Func. Mater. 2016, 26, 5352. [6] Z. Xue, M. Sun, Y. Zhao, Z. Tang, T. Dong, J. Wang, X. Wei, L. Yu, Q. Chen, J. Xu, Y. Shi, K. Chen, P. R. i. Cabarrocas, Nano Lett. 2017, 17, 7638.

Authors : A.-M. Lepadatu1, A. Slav1, C. Palade1, I. Dascalescu 1, M. Enculescu 1, S. Iftimie 2, S. Lazanu1, V. S. Teodorescu1, M. L. Ciurea1, T. Stoica1
Affiliations : 1National Institute of Materials Physics, 077125 Magurele, Bucharest, Romania; 2University of Bucharest, Faculty of Physics, 077125 Magurele, Bucharest, Romania

Resume : Group IV nanostructures, particularly of Ge nanocrystals (NCs) embedded in oxides are promising candidates for photo-effect applications such as photosensing, photovoltaics, light emission and photocatalysis. This is mainly due to the advantage of controlling spectral sensitivity limit by changing the NC size. In this work, we investigate the optical, electrical and photoconductive properties in correlation with the structure properties and morphology of Ge NCs embedded in TiO2 films prepared by magnetron sputtering deposition and subsequent nanostructuring by rapid thermal annealing. For this we use different characterization methods of high resolution transmission electron microscopy, X-ray diffraction, optical transmission and reflectance as well as dark and photocurrent measurements. We evidence different phenomena related to Ge NCs: i) the refractive index shows a deep minimum related to NCs formation; ii) the optical bandgap of Ge NCs is correlated with their size proving the blue-shift due to quantum confinement; iii) Efros-Shklovskii Coulomb-gap variable range hopping is found to be responsible for the temperature dependence of the dark current; iv) the photoconduction is enhanced by the formation of Ge NCs in comparison to the one of as-deposited amorphous films. More than that, we demonstrate the enhancement of photocurrent by field effect that controls the Fermi level at the film-substrate interface.

Authors : M. A. Vieira (1,2), M. Vieira (1,2,3), P. Louro (1,2) , P. Vieira (1,4)
Affiliations : 1Electronics Telecommunication and Computer Dept. ISEL, R. Conselheiro Emídio Navarro, 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, ; 2 CTS-UNINOVA, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal. 3 DEE-FCT-UNL, Quinta da Torre, Monte da Caparica, 2829-516, Caparica, Portugal 4 Instituto de Telecomunicações, Instituto Superior Técnico, 1049-001, Lisboa, Portugal

Resume : The paper proposes the use of Visible Light Communication (VLC) in Vehicular Communication Systems for vehicle safety applications. A smart vehicle lighting system that combines the functions of illumination, signaling, communications, and positioning is presented. The system aims to ensure the communication between a LED based VLC emitter and an on-vehicle VLC receiver. A traffic scenario is stablished. Vehicle-to-vehicle (V2V) and Infrastructure-to-Vehicle (I2V) communications are analyzed. For the V2V communication study, the emitter was developed based on the vehicle head lights, whereas for the study of I2V communication system, the emitter was built based on streetlights. The VLC receiver is used to extract the data from the modulated light beam coming from the white RGB-LEDs emitters. The VLC receiver is based on amorphous SiC technology and enhances the conditioning of the signal enabling to decode the transmitted information. The [p(SiC:H)/i(SiC:H)/n(SiC:H)/p(SiC:H)/i(Si:H)/n(Si:H)] tandem photodetectors are located at the roof-top of the vehicle, for I2V communications, and at the tails for V2V reception. Clusters of emitters, in a square topology, are used in the I2V transmission. The information and the ID code of each emitter in the network are sent, simultaneously, by modulating the individual chips of the trichromatic white LED. Free space is the transmission medium. An on-off code is used to transmit data. An algorithm to decode the information at the receivers is set. The proposed system was tested. The experimental results, confirmed that the proposed cooperative VLC architecture is suitable for the intended applications.

Authors : K. S. Daskalakis, A.I. Väkeväinen, J.-P. Martikainen, T.K. Hakala, and P. Törmä
Affiliations : COMP Centre of Excellence, Department of Applied Physics, Aalto University School of Science, FI-00076 Aalto, Finland

Resume : In this paper we demonstrate an organic dye nanolaser that exhibits ultrafast modulation speed and high beam directionality [1]. The studied nanolaser consists of arrays of cylindrical gold nanoparticles with a diameter of 100 nm and a height of 30 nm, arranged in a square lattice. The periodicity is varied between 565 – 585 nm. To probe the lasing properties, IR-140 dye (5,5΄-dichloro-11- diphenylamine-3,3΄-diethyl-10,12-ethylene-thiatricarbocyanine-perchlorate), in low concentration solutions is deposited on the sample. In this configuration, the sample exhibit lasing at room temperature at infrared wavelength (~ 880 nm). Similar plasmonic lattices have enable lasing at the visible wavelengths in both bright and dark modes [2]. To gain insight into the temporal lasing dynamics of the sample, we utilize a single-colour pump probe approach where we measure the time-integrated photoluminescence (PL) spectrum for varying delays of the weak probe pulse. This pump-probe approach uses the intrinsic nonlinearity in lasing to examine the lasing dynamics [3]. We optically excite the sample at 45° incident angle with a 34-femtosecond pump at λ = 800 nm. Above the threshold of 120 μW, we see a remarkably rapid modulation speed. By realizing a comprehensive above-threshold power dependence of the temporal characteristics of the samples, we observe a strong dependence of the laser dynamics. References: [1] K.S. Daskalakis et al., manuscript under review (2017). [2] T.K. Hakala, H.T. Rekola, A.I. Väkeväinen, J.-P Martikainen, M. Neĉada, A.J. Moilanen & P. Törmä, Nat. Commun. 8, 13687 (2017). [3] T.P.H. Sidiropoulos, R. Röder, S. Geburt, O. Hess, S.A. Maier, C. Ronning & R.F. Oulton, Nat. Phys. 10, 1038 (2014).

Authors : V. F. Gili(1), N. Morais(1), I. Roland(1), S. Suffit(1), A. Lemaitre(2), I. Favero(1), and G. Leo(1)
Affiliations : (1) Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot - Sorbonne Paris Cité, 10 rue A. Domon et L. Duquet, 75013 Paris, France (2) Centre de Nanosciences et de Nanotechnologies, CNRS, Route de Nozay, 91460 Marcoussis, France

Resume : The success of the silicon-on-insulator platform in photonic integrated circuits (PICs) stems from the high refractive index contrast between a thin waveguide and an optical substrate, enabling to pattern sub-µm, strongly confining structures. However, its application to nonlinear photonics suffers from two-photon absorption (TPA) at 1.55 µm and a weak nonlinearity. AlGaAs, the well-known semiconductor laser material, is a promising candidate for an ideal nonlinear photonics platform, thanks to its large energy gap set by the Al molar fraction so at so avoid TPA at 1550 nm, its huge (2), and its transparency up to the mid-infrared. Until recently, however, an efficient fabrication procedure of monolithic AlGaAs-on-insulator has lacked, and the performances of optical devices resting on a low-index substrate obtained by selective oxidation of AlAs have been limited by the shortcomings of this process at the crystal/oxide interface. Here we illustrate a fabrication method allowing for the monolithic integration of AlGaAs nanostructures on a low-index oxide substrate. This platform requires a far simpler technology than wafer-bonded PICs, and it has recently proved its potential in the domain of nonlinear nanophotonics, with the demonstration of high-efficiency frequency conversion at sub-wavelength scale. These results pave the way towards the realization of nonlinear metasurfaces and point towards the implementation of low-cost AlGaAs nonlinear optical circuits on-chip.


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