摘要
理论计算CdS晶格常数为0.5832nm与实验值0.5818nm比较,误差小于1%.理论预测CdS是一种直接宽禁带半导体材料,导带底和价带顶都位于布里渊区中心G点处,直接带隙为1.25eV,比实验值2.42eV小,这是由于密度泛函理论框架决定的.CdS的下价带主要由Cd的4d电子贡献,上价带主要由S的3p电子形成,CdS的导带主要来源于Cd的5s电子和S的3p电子的贡献.CdS晶体中Cd原子失去电子,为电子的给予体,S原子得到电子,是电子受主,且Cd—S键是共价键.Cd—S距离为2.52533,与实验值0.253nm相比更加精确.其介电函数虚部与吸收光谱以及介电函数实部与折射率的峰值位置十分接近,说明它们之间存在内在联系,都与电子态密度分布直接相关.
In comparing the theoretical calculation of CdS lattice constant （0. 5832nm） with the experi- mental data （0. 5818nm）, it is found the error is less than 1%. Theoretical prediction tells CdS is a direct wide band gap semiconductor material, the conduction band and valence band at the end of the top Brillouin zone are located in the center point G, with the direct band-gap as 1.25eV, smaller than the experimental value of 2.42eV, determined by the Theoretical framework of density float function. The under valence band of CdS is mainly contributed by e-4d of Cd, and the up valence band of CdS is mainly formed by the S e-3p, and the conduction band of CdS is mainly contributed by Cd e-5s and the S e-3p. Cd atoms in the crystal CdS lose electrons, hence the electronic donor, and S atoms the electron receiver, and Cd--S is the covalent bond key. Cd-S distance is 2. 52533 ？, more accurate compared with the experimental data of 0 253nm. The imaginary part of dielectric function and the absorption spectrum as well as the real part of di electric function and the refractive index is very close at the peak position, there are internal relations be tween them, and they are directly related to the distribution of electronic state density.
出处
《徐州工程学院学报（自然科学版）》
CAS
2009年第3期76-81,共6页
Journal of Xuzhou Institute of Technology(Natural Sciences Edition)
基金
教育部留学回国人员实验室建设及科研经费资助项目(2003.18)
关键词
CDS
第一性原理
电子结构
光学性质
CdS
first principles
electronic structure
optical properties
