兰州大学机构库 >物理科学与技术学院
三种典型量子点的电子结构及线性光学性质
Alternative TitleElectronic structure and linear optical properties of three quantum dot materials
苏康
Thesis Advisor王育华
2009-05-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword第一性原理 量子点 VASP
AbstractVASP是Vienna Ab-initio Simulation Package的缩写,它是使用赝势和平面波基组,进行从头量子力学分子动力学计算的软件包。VASP中的方法基于有限温度下的局域密度近似(用自由能作为变量)以及对每一MD步骤用有效矩阵对角方案和有效Pulay混合求解瞬时电子基态。这些技术可以避免原始的Car-Parrinello方法存在的一切问题,而后者是基于电子、离子运动方程同时积分的方法。离子和电子的相互作用超缓Vanderbilt赝势(US-PP)或投影扩充波(PAW)方法描述。 本文利用VASP软件包和Materials Studio软件对三种典型量子点经行了理论计算,总结如下: 计算了ZnSe的态密度及能带结构,通过分析态密度可知,价带顶主要是Zn的d轨道占优势,导带底主要来源于Zn的3p轨道,部分来源于Se的s轨道。掺杂后禁带宽度由2.48eV变为1.1eV。 ZnS为直接带隙半导体,禁带宽度约为3.13eV。价带顶由分布的能量范围比较广的S原子的 p 轨道构成,而导带的主要贡献来自Zn的4s轨道。 计算了GaAs的态密度及能带结构,通过分析态密度可知,GaAs带隙的宽度为1.21 eV。三个子带分别出现在-15eV附近,费米能级附近和1.21-22eV范围。
Other AbstractVASP is a package for performing ab-initio quantum-mechanical molecular dynamics (MD) using pseudo potentials and a plane wave basis set. The approach implemented in VASP is based on a finite-temperature local-density approximation (with the free energy as variational quantity) and an exact evaluation of the instantaneous electronic ground state at each MD-step using efficient matrix diagonalization schemes and an efficient Pulay mixing. These techniques avoid all problems occurring in the original Car-Parrinello method which is based on the simultaneous integration of electronic and ionic equations of motion. The interaction between ions and electrons is described using ultrasoft Vanderbilt pseudopotentials (US-PP) or the projector augmented wave method (PAW). Electronic structure of three semiconductor quantum dot materials was calculated using the VASP and Materials Studio. The densities of states and energy band structures of ZnSe were calculated. By analyzing the partial densities of states, the d states of Zn mostly contribute to the valence band, and the 3p states of Zn and the s states of Se have major effects on the conduction band. The calculated results of ZnSe: Mn show the band gap was changed from 2.48 to 1.1eV. The band gap of theZnS is about 3.13 eV, the p states of S mostly contribute to the top of the valence band, and the s states of Zn have major effects on the bottom of the conduction band. The densities of states and energy band structures of GaAs were calculated. By analyzing the partial densities of states, the band gap of GaAs is 1.21eV. Three of Sub-band of DOS was the peak about -15eV, in the near of Fermi level and the range of 1.21-22eV.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229417
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
苏康. 三种典型量子点的电子结构及线性光学性质[D]. 兰州. 兰州大学,2009.
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