First principles calculation of growth dynamics and electronic properties of heterovalent burried-vacancy interfaces

异价埋入空位界面生长动力学和电子性质的第一性原理计算

基本信息

批准号：
10640298
负责人：
NAKAYAMA Takashi
金额：
$ 1.6万
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：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

We have clarified formation dynamics and electronic properties of heterovalent vacancy-contained interfaces as follows, by using the first-principles calculations and the crystal growth simulations.1. Development of crystal growth simulator ; Monte Carlo crystal-growth simulations are developed, which are based on the first-principles calculations and take into account the four coordination of atoms, the surface dimer formation, the inter-bond transfer of excess charge, the long-range atom diffusion and the strain effects.2. ZnSe/GaAs (110) and (001) interfaces ; Due to the relaxation of charge mismatch, the atomically sharp interface is easily formed at the (110) nonpolar interface. On the other hand, we found for the (001) interface that (1) the simultaneous supply of Zn and Se atoms often produces the Se antisites which induce vacancy defects and stacking faults, (2) the initial supply of only Zn atoms extinguishes such antisites, (3) the initial supply of Se promotes the As evapola … More tion and produces GaSe layers having rough surfaces. It was proved that all these results originate from the heterovalency between GaAs and ZnSe compounds and well explain the observations.3. ZnO/GaN (0001) interfaces ; At the initial growth, the interface excess charge promotes the growth by moving to the surface, while at the later stage it is strongly localized at the interface and has no effects on the growth. The resulting interface has type-II offset.4. Vacancy compounds ; We showed that the vacancy-layered wurtzite In_2Se_3, which has large anisotropy around the absorption gap, grows along (111) with three period to relax the strain, the vacancy ternary compounds such as CdGa_2Se_4 show the large band-gap variation depending on the vacancy ordering, and the vacancy arrangement is easily observed by the Raman scattering experiments.5. Other interfaces ; We clarified that the growth of InAs wetting layers on GaAs (001) promotes cation mixing, the reflectance difference spectra of Si (001) oscillate during the oxidation, and the limitting process by Cl to etch the Si (111) surface is not the diffusion but the desorption. Less

通过第一性原理计算和晶体生长模拟，我们阐明了含异价空位界面的形成动力学和电子性质： 1．开发了基于蒙特卡罗晶体生长模拟的晶体生长模拟器。基于第一性原理计算，考虑了原子的四配位、表面二聚体的形成、键间多余电荷的转移、原子的长程扩散和应变效应。 2． ZnSe/GaAs（110）和（001）界面；由于电荷失配的松弛，在（110）非极性界面处容易形成原子尖锐界面；另一方面，我们发现（001）界面（ 1) 同时供应 Zn 和 Se 原子通常会产生 Se 反位，从而引起空位缺陷和堆垛层错，(2) 最初仅供应 Zn 原子会消除此类反位， (3) Se 的初始供应促进了 As 蒸发并产生了具有粗糙表面的 GaSe 层。事实证明，所有这些结果都源于 GaAs 和 ZnSe 化合物之间的异价性，并很好地解释了 ZnO/GaN 的观察结果。 (0001) 界面；在生长初期，界面多余电荷通过移动到表面来强烈促进生长，而在后期，它集中在界面处，对生成的界面没有影响。 4. 空位化合物；我们发现，空位层状纤锌矿In_2Se_3在吸收带隙附近具有较大的各向异性，沿着（111）方向生长以松弛应变，空位三元化合物如CdGa_2Se_4表现出带隙的变化取决于空位的排序，并且空位的排列很容易通过拉曼散射实验观察到。5．我们阐明了GaAs（001）上InAs润湿层的生长促进了阳离子混合，Si（001）的反射差光谱在氧化过程中振荡，并且Cl蚀刻Si（111）表面的限制过程不是扩散但解吸量较少。