Pub Date : 2022-06-01DOI: 10.1109/CSW55288.2022.9930439
I. H. Rodrigues, A. Vorobiev
We present a preliminary study of charge carrier transport in graphene field-effect transistor with gate lengths ranging from 2 μm down to 0.2 μm applying a model of the quasi-ballistic charge carrier transport. The analysis indicates that, in particular, at the gate length of 0.2 μm the fraction of the ballistic carriers can be up to 60 %. Our finding can be used as a guidance for further development of the graphene field-effect transistors with submicron gate length for variety of the advanced and emerging applications.
{"title":"Charge carrier transport in graphene field-effect transistor scaled down to submicron gate lengths","authors":"I. H. Rodrigues, A. Vorobiev","doi":"10.1109/CSW55288.2022.9930439","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930439","url":null,"abstract":"We present a preliminary study of charge carrier transport in graphene field-effect transistor with gate lengths ranging from 2 μm down to 0.2 μm applying a model of the quasi-ballistic charge carrier transport. The analysis indicates that, in particular, at the gate length of 0.2 μm the fraction of the ballistic carriers can be up to 60 %. Our finding can be used as a guidance for further development of the graphene field-effect transistors with submicron gate length for variety of the advanced and emerging applications.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126113640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-28DOI: 10.1109/CSW55288.2022.9930379
A. Krishna, A. Raj, N. Hatui, S. Keller, U. Mishra
This study experimentally shows the existence of acceptor traps at positive polarization interfaces acting as the source of holes in Ga-polar p-type uniformly doped (AlGaN/AlN)/GaN superlattices with low Mg doping. The observed hole concentrations which exceed that of the dopants (here, Mg) incorporated into the samples during growth, can be explained by the ionization of acceptor traps, placed 0.8 eV above the valence band of GaN, at positive polarization interfaces. All samples were epitaxially grown using Metal Organic Chemical Vapor Deposition, and were characterized using X-Ray Diffraction and room-temperature Hall measurements. The measured hole concentrations are compared to calculated values from STR FETIS® and the measured mobility trends are explained using the separation of the positive polation interfaces from the two-dimensional hole gas in the systems, strengthening the hypothesis.
{"title":"Demonstration of acceptor-like traps at positive polarization interfaces in Ga-polar p-type (AlGaN/AlN)/GaN superlattices","authors":"A. Krishna, A. Raj, N. Hatui, S. Keller, U. Mishra","doi":"10.1109/CSW55288.2022.9930379","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930379","url":null,"abstract":"This study experimentally shows the existence of acceptor traps at positive polarization interfaces acting as the source of holes in Ga-polar p-type uniformly doped (AlGaN/AlN)/GaN superlattices with low Mg doping. The observed hole concentrations which exceed that of the dopants (here, Mg) incorporated into the samples during growth, can be explained by the ionization of acceptor traps, placed 0.8 eV above the valence band of GaN, at positive polarization interfaces. All samples were epitaxially grown using Metal Organic Chemical Vapor Deposition, and were characterized using X-Ray Diffraction and room-temperature Hall measurements. The measured hole concentrations are compared to calculated values from STR FETIS® and the measured mobility trends are explained using the separation of the positive polation interfaces from the two-dimensional hole gas in the systems, strengthening the hypothesis.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127865146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-01DOI: 10.1109/csw55288.2022.9930455
George T. Wang, K. Sapkota, Albert Talin, F. Léonard, B. Gunning, G. Vizkelethy
The III-nitride semiconductors are attractive for on-chip, solid-state vacuum nanoelectronics, having high thermal and chemical stability, low electron affinity, and high breakdown fields. Here we report top-down fabricated, lateral gallium nitride (GaN)-based nanoscale vacuum electron diodes operable in air, with ultra-low turn-on voltages down to ~0.24 V, and stable high field emission currents, tested up to several microamps for single-emitter devices. We present gap-size and pressure dependent studies which provide insights into the design of future nanogap vacuum electron devices. The vacuum nanodiodes also show high resistance to damage from 2.5 MeV proton exposure. Preliminary results on the fabrication and characteristics of lateral GaN nano vacuum transistors will also be presented. The results show promise for a new class of robust, integrated, III-nitride based vacuum nanoelectronics.
iii -氮化物半导体具有高热稳定性和化学稳定性、低电子亲和性和高击穿场等特点，是片上固态真空纳米电子学研究的热点。本文报道了自顶向下制造的横向氮化镓(GaN)纳米级真空电子二极管，该二极管可在空气中工作，具有低至~0.24 V的超低导通电压和稳定的高场发射电流，在单发射极器件上测试了高达几微安的电流。我们提出了间隙大小和压力相关的研究，为未来纳米间隙真空电子器件的设计提供了见解。真空纳米二极管还显示出对2.5 MeV质子暴露的高抗损伤性。本文还将介绍横向氮化镓纳米真空晶体管的制备和特性的初步结果。研究结果显示了一种新型的鲁棒、集成、iii -氮化物基真空纳米电子学的前景。
{"title":"Ultra-low Voltage GaN Vacuum Nanoelectronics","authors":"George T. Wang, K. Sapkota, Albert Talin, F. Léonard, B. Gunning, G. Vizkelethy","doi":"10.1109/csw55288.2022.9930455","DOIUrl":"https://doi.org/10.1109/csw55288.2022.9930455","url":null,"abstract":"The III-nitride semiconductors are attractive for on-chip, solid-state vacuum nanoelectronics, having high thermal and chemical stability, low electron affinity, and high breakdown fields. Here we report top-down fabricated, lateral gallium nitride (GaN)-based nanoscale vacuum electron diodes operable in air, with ultra-low turn-on voltages down to ~0.24 V, and stable high field emission currents, tested up to several microamps for single-emitter devices. We present gap-size and pressure dependent studies which provide insights into the design of future nanogap vacuum electron devices. The vacuum nanodiodes also show high resistance to damage from 2.5 MeV proton exposure. Preliminary results on the fabrication and characteristics of lateral GaN nano vacuum transistors will also be presented. The results show promise for a new class of robust, integrated, III-nitride based vacuum nanoelectronics.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121804417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-08DOI: 10.1109/CSW55288.2022.9930369
F. del Giudice, S. Fust, P. Schmiedeke, Johannes Pantle, M. Döblinger, A. Ajay, Steffen Meder, H. Riedl, J. Finley, G. Koblmüller
InAs-AlAsSb core-shell nanowire (NW) systems with widely tunable AlAsSb shell composition may offer many ideal properties suited for forthcoming applications in nanoelectronics, energy harvesting, as well as mid-infrared (MIR) photonics and optoelectronics integrated on silicon (Si). Here, we present high-uniformity InAs-AlAsSb NW arrays grown by selective-area molecular beam epitaxy. Further, we study systematically the effects of shell composition on the morphological, structural as well as strain and optical properties using correlated electron microscopy techniques, combined with micro-Raman scattering and micro-photoluminescence spectroscopy (PL). While controlling the emission wavelength over a large range (~0.4–0.55 eV), we highlight the tunability between type-I and type-II like transitions in this system supported by simulations.
{"title":"Epitaxial type-I and type-II InAs-AlAsSb core–shell nanowires on silicon","authors":"F. del Giudice, S. Fust, P. Schmiedeke, Johannes Pantle, M. Döblinger, A. Ajay, Steffen Meder, H. Riedl, J. Finley, G. Koblmüller","doi":"10.1109/CSW55288.2022.9930369","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930369","url":null,"abstract":"InAs-AlAsSb core-shell nanowire (NW) systems with widely tunable AlAsSb shell composition may offer many ideal properties suited for forthcoming applications in nanoelectronics, energy harvesting, as well as mid-infrared (MIR) photonics and optoelectronics integrated on silicon (Si). Here, we present high-uniformity InAs-AlAsSb NW arrays grown by selective-area molecular beam epitaxy. Further, we study systematically the effects of shell composition on the morphological, structural as well as strain and optical properties using correlated electron microscopy techniques, combined with micro-Raman scattering and micro-photoluminescence spectroscopy (PL). While controlling the emission wavelength over a large range (~0.4–0.55 eV), we highlight the tunability between type-I and type-II like transitions in this system supported by simulations.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125171274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-05DOI: 10.1109/CSW55288.2022.9930368
M. Meyer, S. Schmid, F. Jabeen, G. Bastard, Fabian Hartmann, S. Höfling
We present gate voltage and temperature dependent transport measurements of topological insulators based on InAs/GaSb/InAs triple quantum wells (TQW). Gate voltage dependent measurements enable us to monitor two electrons densities deep in the nonhybridized electron regime related to both InAs-wells. Furthermore, they reveal a clear hybridization gap and a Van Hove singularity (VHS) in the valence band (VB) because of the hybridized electron-hole band structure. Electron and hole densities coexist if the Fermi energy (EF) is within the gap and the bottom of the valence band at the Γ point whereas only single carrier types can be found far in the conduction or valence band. Thus, we are able to identify the topological band structure of this material system. Additionally, we study the temperature evolution of the hybridization gap and find a rather temperature insensitive hybridization gap energy.
{"title":"Topological band structure in InAs/GaSb/InAs triple quantum wells","authors":"M. Meyer, S. Schmid, F. Jabeen, G. Bastard, Fabian Hartmann, S. Höfling","doi":"10.1109/CSW55288.2022.9930368","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930368","url":null,"abstract":"We present gate voltage and temperature dependent transport measurements of topological insulators based on InAs/GaSb/InAs triple quantum wells (TQW). Gate voltage dependent measurements enable us to monitor two electrons densities deep in the nonhybridized electron regime related to both InAs-wells. Furthermore, they reveal a clear hybridization gap and a Van Hove singularity (VHS) in the valence band (VB) because of the hybridized electron-hole band structure. Electron and hole densities coexist if the Fermi energy (EF) is within the gap and the bottom of the valence band at the Γ point whereas only single carrier types can be found far in the conduction or valence band. Thus, we are able to identify the topological band structure of this material system. Additionally, we study the temperature evolution of the hybridization gap and find a rather temperature insensitive hybridization gap energy.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126264271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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