AlGaN/GaN异质结重构层结构及其性质的理论研究
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- 英文论文题名：Theoretical study on the reconstructions and electronic properties of AlGaN/GaN heterojunctions
- 论文作者：易文才 ; 刘靖尧 ; 苗茂生
- 英文论文作者：Wencai Yi ; Jingyao Liu ; Maosheng Miao ; Institute of Theoretical Chemistry ; Jilin University ; Department of Chemistry & Biochemistry ; California State University ; Beijing Computational Science Research Center
- 年：2016
- 作者机构：吉林大学理论化学研究所;美国加州州立大学北岭分校化学与生物化学部;北京计算科学研究中心;
- 论文关键词：AlGaN ; 表面重构 ; 二维电子气 ; 密度泛函理论计算
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第四十分会：纳米体系理论与模拟
- 语种：中文
- 分类号：O647
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十分会 ; 纳米体系理论与模拟
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：143k
- 原文格式：D
- 会议级别：全国
摘要
AlGaN/GaN由于其高电子迁移率而被广泛应用于高压、高能以及高温电子设备。AlGaN/GaN异质结界面常常生长在GaN晶体[001]方向并展现出高密度的二维电子气(2DEG)特性。以往研究认为AlGaN/GaN表面的捐赠态是2DEG的主要产生来源。2010年,Miao等人1,2依据电子计数规则(ECR)和化学组分匹配(OS)构建了8种不同的AlGaN/GaN(大约2层厚度)氧化重构结构解释了2DEG的现象来源。然而,对AlGaN异质结表/界面可能的微观结构以及2DEG具体产生的机制仍有待进一步地探索。本文利用粒子群(PSO)进化算法对AlGaN/GaN所有可能的氧化层结构进行了系统的结构搜索,搜索结果不仅很好地重现了以往的结构,还发现了一些能量更低更具有竞争力的结构。通过对这些新结构的电子结构计算,我们认为OS双层结构在能量上更具有竞争性,其表面捐赠态是AlGaN/GaN异质结形成2DEG的主要原因。
AlGaN/GaN and t transistor(HEMTs) have received intensive attention for their wide applications in high-voltage, high-power, and high-temperature microwave electron devices due to the associated high electron mobility. In this paper, we apply Particle Swarm Optimization(PSO) Algorithm to predict the possible surface reconstructions on realistic GaN and AlN [001] surfaces, which are invariably oxidized. All the structures proposed by previous reports were reproduced and a number of new stable surface reconstructions with lower formation energy were identified. Further electronic structure calculations reveal that the oxide-stoichiometry(OS)-matching bilayer structures have more advantages in energy compared to the electron counting(EC)-matching structures and are the main source of the two-dimensional electron gas(2DEG) at the AlGaN/GaN interface.
AlGaN/GaN and t transistor(HEMTs) have received intensive attention for their wide applications in high-voltage, high-power, and high-temperature microwave electron devices due to the associated high electron mobility. In this paper, we apply Particle Swarm Optimization(PSO) Algorithm to predict the possible surface reconstructions on realistic GaN and AlN [001] surfaces, which are invariably oxidized. All the structures proposed by previous reports were reproduced and a number of new stable surface reconstructions with lower formation energy were identified. Further electronic structure calculations reveal that the oxide-stoichiometry(OS)-matching bilayer structures have more advantages in energy compared to the electron counting(EC)-matching structures and are the main source of the two-dimensional electron gas(2DEG) at the AlGaN/GaN interface.
引文
[1]Miao,M.;Janotti,A.;Van de Walle,C.Physical Review B2009,80,155319
[2]Miao,M.S.;Weber,J.R.;Van de Walle,C.G.J Appl Phys2010,107,123713.
[2]Miao,M.S.;Weber,J.R.;Van de Walle,C.G.J Appl Phys2010,107,123713.