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First principles calculation of optical spectra of GaAs growing surface structures

GaAs生长表面结构光谱的第一性原理计算

基本信息

批准号：
08640410
负责人：
NAKAYAMA Takashi
金额：
$ 1.34万
依托单位：
Chiba University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

We have developed the method to calculate the reflectance difference spectra (RDS) and clarified the electronic structures of growing semiconductor surfaces and interfaces from optical viewpoints as follows.1.Spectra origin and local field effect ; when the electronic states are localized (extended) around the surface/interface, the optical transitions between surface states (bulk states) produce peak-shaped (epsilon_2-derivative-shaped) spectra. From the various layr-thickness calculations, the local field is shown having about 50 contributions to the spectra.2.(001) anion surfaces ; the dangling-bond states of surface anion-dimer atoms produce the large peak structures in GaAs and ZnSe surface spectra. The peak position and width respectively increase by 0.77eV/ and 0.5eV/ with decreasing the dimer distance, which well explains the recent experiments by Kobayashi et al.3.(001) cation surfaces ; the cation atoms on the top layr largely sink into bulks to stabilize by producing sp^2/sp … More bonding, which stands up the dangling-bond states of the second-top-layr anions perpendicular to the surface. The optical transition from such states to the conduction-band states produces the characteristic peak structures, which feature is particularly remarkable for ZnSe surfaces.4.Adsorbed (001) surfaces and interfaces ; depending on the relative energy position between GaAs bands and orbital energies of adsorbed atoms, the spectra intensity has the order of Sb>P>N for GaAs surfaces. When the thickness of hetero-epitaxialized atomic layrs is more than five, the interface spectra show the epsilon_2-derivative shape, which results explain the recent experiments of ZnSe/GaAs interfaces by Yasuda et al.5.(110) nonpolar GaAs surfaces ; reflecting the buckling reconstructions, the optical transitions between the dangling-bond states of As and Ga and the anti-bonding states of Ga-As surface bonds produce the large peaks, which results can be used to determine the adsorption sites on growth. Less

我们发展了计算反射差谱（RDS）的方法，从光学角度阐明了生长半导体表面和界面的电子结构：1.光谱起源和局域场效应：当电子态在表面/界面附近局域（扩展）时，表面态（体态）之间的光学跃迁产生峰形（ε_2-导数形）光谱。从各种层厚度计算，局部场显示具有约50的贡献的光谱。(001)阴离子表面，表面阴离子二聚体原子的悬键态在GaAs和ZnSe表面光谱中产生大峰结构。随着二聚体距离的减小，峰位和峰宽分别增加0.77 eV/和0.5 eV/，这很好地解释了小林等人最近的实验。(001)阳离子表面;顶层的阳离子原子大部分下沉到大块中，通过产生sp^2/sp来稳定 ...更多信息成键，其使第二顶层阴离子的悬挂键态垂直于表面。从这些态到导带态的光学跃迁产生了特征峰结构，这一特征在ZnSe表面尤为显著。4.吸附（001）表面和界面，根据GaAs能带间的相对能量位置和吸附原子的轨道能量，GaAs表面的光谱强度顺序为Sb>P>N。当异质外延原子层的厚度大于5时，界面谱呈现出ε_2-导数的形状，这一结果解释了Yasuda等人最近关于ZnSe/GaAs界面的实验结果。(110)非极性GaAs表面; As和Ga的悬挂键态与Ga-As表面键的反键态之间的光学跃迁产生了大的峰，反映了屈曲重构，其结果可用于确定生长过程中的吸附位置。少