空位浓度对纤锌矿CdS电子结构和光学性质影响的第一性原理研究

本文基于密度泛函理论的平面波超软赝势方法,采用第一性原理研究了含Cd空位缺陷CdS和含S空位缺陷纤锌矿CdS的几何结构、能带结构、电子态密度及光学性质。通过计算分析可知,含Cd空位缺陷的CdS体系均为p型半导体,含S空位缺陷的CdS体系跃迁方式均由直接跃迁变为间接跃迁。Cd、S空位缺陷的CdS体系的态密度总能量降低。空位CdS体系相较于本征CdS体系的静介电常数均有提高,并随着空位浓度的增大而增大,Cd空位缺陷体系更为明显,极化能力得到显著提升。空位Cd的CdS体系相较于本征CdS体系在红外波段存在明显的吸收,空位S的CdS体系相较于本征CdS体系在可见光波段存在明显的吸收。

First-Principles Study on the Effect of Vacancy Concentration on the Electronic Structure and Optical Properties of Wurtzite CdS

Based on the plane wave ultra soft pseudopotential method of density functional theory, the geometric structure, energy band structure, electronic density of states and optical properties of wurtzite CdS containing Cd vacancy defect and wurtzite CdS containing S vacancy defect were studied by the first-principle. According to calculation and analysis, the CdS systems containing Cd vacancy defects are all p-type semiconductors and the transition modes of CdS systems containing S vacancy defects are all changed from direct transition to indirect transition. The density of states and total energy of CdS system with Cd and S vacancy defects decrease. The static dielectric constant of vacancy CdS system is higher than that of intrinsic CdS system, and increases with the increase of vacancy concentration. The vacancy defect system of Cd is more obvious, and the polarization ability is significantly improved. The CdS system of Cd vacancy has obvious absorption in infrared band compared with the intrinsic CdS system, and the CdS system of S vacancy has obvious absorption in visible light compared with the intrinsic CdS system.