ZnSe掺Cu与Zn空位缺陷的稳定性、电子结构与光学性质

采用基于密度泛函理论框架下的第一性原理平面波超软雁势方法, 对ZnSe闪锌矿结构本体、掺入p型杂质Cu(Zn_0.875Cu_0.125Se)及Zn空位(Zn_0.875Se)超晶胞进行结构优化处理. 计算并详细分析了缺陷体系的形成能和三种体系下ZnSe材料的态密度、能带结构、集居数、介电和吸收光谱. 结果表明: 在Zn空位与Cu掺杂ZnSe体系中, 由于空位及杂质能级的引入, 禁带宽度有所减小, 吸收光谱产生红移; 单空位缺陷结构不易形成, Zn_0.875Se结构不稳定, Cu掺杂ZnSe结构相对更稳定.

Defects Energetics,Electronic Structure and Optical Properties of Cu-Doping and Zn Vacancy Impurities in ZnSe

Based on first-principles within the density functional theory, the geometric structures of perfect zinc blend ZnSe, that with Zn vacancies (Zn_0.875Se) and Cu-doped ZnSe(Zn_0.875Cu_0.125Se) were optimized using the plane-wave ultrasoft pseudopotential method. The defect formation energy, band structure, density of states, mulliken charges, and optical spectra were calculated and discussed in detail. The results demonstrated that in Zn_0.875Se and Zn_0.875Cu_0.125Se systems, because of the introduction of the vacancy acceptor level or acceptor impurity level, the band gap is reduced, and the absorption peaks show a remarkable redshift. Cu doping into the ZnSe system was found to be relatively stable, while the monovacancy system was not.