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Polarization—Induced Charges in Modulation—Doped AlxGa1—xN／GaN Heterostructures through Capacitance—Voltage Profiling

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Chinese Physics Letters 2002年第8期19卷 1172-1175页

作者：周玉刚 t.someya 等 NationalLaboratoryofSolidStateMicrostructuresandDepartmentofPhysics NanjingUniversityNanjing210093 ResearchCenterforAdvancedScienceandtechnologyandInstituteofIndustrialScience

Polarization-induced charges in modulation-doped Al0.22Ga0.78N/GaN heterostructures were investigated by the capacitance-voltage (C-V) method. the C-V profile of the Pt/Al0.22Ga0.78N/GaN Schottky diodes with various Al0.22Ga0.78N thicknesses shows significant differences due to change of the polarization field in the heterostructures. A numerical simulation based on the experimental results indicates that the sheet density of the polarization-induced charges at the heterointerface is 6.78×1012cm-2 in the samples with the Al0.22Ga0.78N thicknesses of 30nm or 45nm. the charge density reduces to 1.30×1012cm-2 in the sample with the Al0.22Ga0.78N thickness of 75nm. It is thought that the reduction of the polarization-induced charges at the heterointerface is due to the partial relaxation of the Al0.22Ga0.78N layer on GaN. this work provides a technique for quantitative characterization of the polarization-induced charges in AlxGa1-xN/GaN heterostructures.

关键词： Polarization-Induced Charges Modulation-Doped Al_xGa_(1-x)N/GaN Heterostructures Capacitance-Voltage Profiling

Growth and Characterization of Modulation-Doped Al_(x)Ga_(1-x)N/GaN Heterostructures

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Chinese Physics Letters 2001年第1期18卷 129-131页

作者： SHEN Bo ZHANG Rong SHI Yi ZHENG You-Dou t.someya Y.Arakawa National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093 Research Center for Advanced Science and technology and Institute of Industrial ScienceUniversity of Tokyo4-6-1 KomabaMeguro-kuTokyo 153-8904Japan

the modulation-doped Al_(0.22)Ga_(0.78)N/GaN heterostructures with different Al_(0.22)Ga_(0.78)N barrier thicknesses were grown by means of metal--organic chemical vapour *** Al_(0.22)Ga_(0.78)N layer still has pseudomorphic growth when its thickness is *** mobility of the two-dimensional electron gas(2DEG)at the heterointerfaces is much higher than that of the electrons in GaN films at both 300 and *** dramatic decrease of the 2DEG mobility in an Al_(0.22)Ga_(0.78)N/GaN heterostructure corresponds to the partial relaxation of the Al_(0.22)Ga_(0.78)N barrier.

关键词： N/Ga deposition mobility

电容-电压法研究Al_xGa_1-xN/GaN异质结压电极化效应（英文）

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发光学报 2001年第Z1期22卷 61-66页

作者：俞慧强沈波周玉刚张荣刘杰周慧梅施毅郑有炓 someya t Arakawa Y 南京大学物理系固体微结构国家重点实验室 Research Center for Advanced Science and technology and Institute of Industrial Science University of Tokyo

制备了基于调制掺杂Al0 2 2 Ga0 78N/GaN异质结的Pt/Al0 2 2 Ga0 78N/GaN肖特基二极管。由于Al0 2 2Ga0 78N势垒层中的极化场不同 ,不同Al0 2 2 Ga0 78N势垒层厚度的二极管的电容电压特性显著不同。根据对样品电容电压特性的... 详细信息

制备了基于调制掺杂Al0 2 2 Ga0 78N/GaN异质结的Pt/Al0 2 2 Ga0 78N/GaN肖特基二极管。由于Al0 2 2Ga0 78N势垒层中的极化场不同 ,不同Al0 2 2 Ga0 78N势垒层厚度的二极管的电容电压特性显著不同。根据对样品电容电压特性的数值模拟 ,在Al0 2 2 Ga0 78N势垒层厚度为 30nm和 4 5nm的样品中 ,异质界面的极化电荷面密度为 6 78× 1 0 12 cm-2 。在Al0 2 2 Ga0 78N势垒层厚度为 75nm的样品中 ,极化电荷面密度降为 1 30×10 12 cm-2 。这种极化电荷面密度的降低是由于GaN上Al0 2 2 Ga0 78N势垒层由于厚度增加而产生应变的部分弛豫。本工作也提供了一种定量表征AlxGa1-xN/GaN异质结中极化电荷面密度的方法。

关键词：压电极化异质结电容电压方法

Pb(Zr_0.53ti_0.47)O₃/Al_xGa_1-xN/GaN异质结构的电容-电压特征（英文）

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发光学报 2001年第Z1期22卷 57-60页

作者：沈波李卫平周玉刚毕朝霞张荣郑泽伟刘杰周慧梅施毅刘治国郑有炓 someya t Arakawa Y 南京大学物理系固体微结构国家重点实验室 Research Center for Advanced Science and technology and Institute of Industrial Science University of Tokyo

通过在调制掺杂Al0 2 2 Ga0 78N/GaN异质结构上淀积Pb(Zr0 53 ti0 4 7)O3 (PZt)铁电薄膜 ,我们发展了一种基于AlxGa1-xN/GaN异质结构的金属铁电半导体 (MFS)结构。在高频电容电压 (C V)特性测量中 ,发现Al0 2 2 Ga0 78N/GaN... 详细信息

通过在调制掺杂Al0 2 2 Ga0 78N/GaN异质结构上淀积Pb(Zr0 53 ti0 4 7)O3 (PZt)铁电薄膜 ,我们发展了一种基于AlxGa1-xN/GaN异质结构的金属铁电半导体 (MFS)结构。在高频电容电压 (C V)特性测量中 ,发现Al0 2 2 Ga0 78N/GaN异质界面二维电子气 ( 2DEG)的浓度在 -1 0V偏压下从 1 5 6× 1 0 13 cm-2 下降为 5 6× 1 0 12 cm-2 。由于PZt薄膜的铁电极化 ,在 -1 0V偏压下可以观察到宽度为 0 2V的铁电C V窗口 ,表明在没有铁电极化方向反转的条件下 ,PZt/AlxGa1-xN/GaNMFS结构也能出现存储特性。因为 2DEG带来的各种优点 ,可以认为AlxGa1-xN/GaN异质结构在以存储器为目标的MFS场效应晶体管中有重要应用。

关键词： C-V特性 Pb(Zrti)O3 铁电薄膜 AlxGa1-xN/GaN

Al_xGa_(1-x)N/GaN异质结二维电子气磁输运性质研究(英文)

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发光学报 2001年第S1期22卷 67-70页

作者：郑泽伟沈波刘杰周慧梅钱悦张荣施毅郑有火斗蒋春萍郭少令郑国珍褚君浩 someya t Arakawa Y 南京大学物理系江苏南京210093 中国科学院上海技术物理研究所红外物理国家重点实验室上海200083 Research Center for Advanced Science and technology and Institute of Industrial Science

在 1 5K低温和 0～ 9t的高磁场下研究了AlGaG/GaN异质结二维电子气的磁输运性质。实验结果在 4块样品中都观察到了Shubnikov daHass振荡的双周期行为。表明异质结的三角势阱中有两个子带被电子占据。通过电子子带占据时电子浓度分配的... 详细信息

在 1 5K低温和 0～ 9t的高磁场下研究了AlGaG/GaN异质结二维电子气的磁输运性质。实验结果在 4块样品中都观察到了Shubnikov daHass振荡的双周期行为。表明异质结的三角势阱中有两个子带被电子占据。通过电子子带占据时电子浓度分配的线形行为得到第二子带被占据的阈值浓度为 7 2× 1 0 12 cm-2 。通过对不同样品量子散射时间和输运迁移率的研究 ,说明在 1 5K下远程离化施主散射在量子散射时间中起主要作用。

关键词：磁传输特性二维电子气 AlxG1-xN/GaN

Detection of apoptosis by Rt-PCR array in mefloquine-induced cochlear damage

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Journal of Otology 2011年第1期6卷 1-9页

作者： DING Da-lian someya Shinichi JIANG Hai-yan QI Wei-dong YU Dong-zhen Center for Hearing and Deafness State University of New York at Buffalo Departments of Aging and Geriatric Research Division of Biology of Aging University of Florida Department of Otolaryngology Head and Neck Surgery Huashan Hospital Affiliated Fudan University Department of Otolaryngology Head and Neck Surgery Six People＇s Hospital of Shanghai Jiao Tong University Graduate School of Agricultural and Life Sciences University of Tokyo Department of Otolaryngology Head and Neck Surgery Xiangya Hospital of Central South University

Objective to investigate the occurrence and possible mechanisms of apoptosis in cochlear epithelium and spiral ganglion neurons after mefloquine treatment. Methods We used quantitative Rt-PCR apoptosis-focused gene arrays （96-well, 84 apoptosis related genes） to assess changes of gene expression in the cochlear basilar membrane （hair cells-supporting cells） and spiral ganglion neurons of rat cochlear organotypic cultures treated with 100 IxM mefloquine for 3 h. Results Significant up-or down-regulation in gene expression was detected in 23 genes in the cochlear basilar membrane, and in 32 genes in the spiral ganglion neurons compared with time-matched controls. the responding genes could be classified as pro-or anti-apoptotic, and were mainly implicated in the Bcl-2, Caspase, Card, IAP, tNF ligand / tNF receptor, Death domain / Death effector domain, DNA damage / p53, and NF-kappa B families. Synthetic analysis suggested that these families could be revised to two major pathways mainly involved in t]he death receptor-mediated signaling pathway and apoptotic mitochondrial pathway. In addition, it was found that numerous anti-apoptotic genes such as Bcl2al, Birclb, Birc3, Birc4, Bnipl, Cflar, II10, Lhx4, Mcll, Nfkbl, Prlr, Prok2, and tNF were greatly up-regulated in the cochlear tissue, which might imply the co-existence of protective response in the ceils at the early stage of mefloquine-induced damage.

关键词： mefloquine ototoxicity apoptosis cochlea spiral ganglion neurons hair cells gene expression

Identification of advanced spin-driven thermoelectric materials via interpretable machine learning

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npj Computational Materials 2019年第1期5卷 232-237页

作者： Yuma Iwasaki Ryohto Sawada Valentin Stanev Masahiko Ishida Akihiro Kirihara Yasutomo Omori Hiroko someya Ichiro takeuchi Eiji Saitoh Shinichi Yorozu Central Research Laboratories NEC CorporationTsukuba 305-8501Japan PRESt JSTSaitama 322-0012Japan Department of Materials Science and Engineering University of MarylandCollege ParkMD 20742USA Center for Nanophysics and Advanced Materials University of MarylandCollege ParkMD 20742USA Joint Quantum Institute University of MarylandCollege ParkMD 20742USA Institute for Materials Research Tohoku UniversitySendai 908-8577Japan WPI Advanced Institute for Materials Research Tohoku UniversitySendai 908-8577Japan Advanced Science Research Center Japan Atomic Energy AgencyTokai 319-1195Japan RIKEN Center for Emergent Matter Science Wako 351-0198Japan

Machine learning is becoming a valuable tool for scientific *** attractive is the application of machine learning methods to the field of materials development,which enables innovations by discovering new and better functional *** apply machine learning to actual materials development,close collaboration between scientists and machine learning tools is ***,such collaboration has been so far impeded by the black box nature of many machine learning *** is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and ***,we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts(FAB/HMEs).Based on prior knowledge of material science and physics,we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric *** by this,we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric *** material shows the largest thermopower to date.

关键词： becoming learning attractive