Ag、N掺杂ZnS结构及光学性质的理论研究

Theoretical Study on Structures and Photocatalytic Properties of Ag,N doped ZnS

本文基于密度泛函理论,采用第一性原理方法研究了Ag、N单掺杂/共掺杂的ZnS结构、能带及光学性质等,结果表明,Ag单掺杂后晶格体积增大,N单掺杂后的晶格体积减小,但二者均可使禁带宽度变窄。在Ag、N共掺杂体系中,Ag、N相邻时,晶格参数的变化较大,而非邻位掺杂时,带隙宽度更小,同时,N的2p态与Zn的3d态在价带深能级的局域化作用减弱,有助于光生电子的跃迁。光学性质计算表明,Ag、N非邻位共掺杂时,体系在低能区的介电常数虚部峰值较大,对可见光的吸收增强,预示掺杂后的ZnS有更好的光催化性能。

The structure, band gaps and optical properties of ZnS with Ag, N single-and co-doped systems were studied by the first-principle calculations based on density functional theory.The volume of the lattice was expanded after single-doping of Ag and compressed after N single-doping.Both systems above could lead to narrower energy gaps.In the co-doped systems, the lattice parameters varied larger when Ag and N in the adjacent sites.The energy gaps were getting narrower when Ag and N were non-adjacent.The localization of the 2 p of N and 3 d of Zn would be weakened in the deep zone of valence band at the same time, which would direct to more efficient transition of the photogenerated electrons.The optical property calculations showed that a higher peak of the imaginary part for the dielectric constant would appear in the low-energy region for non-adjacent co-doped systems.This character suggested stronger absorption in the visible light region and better photo-catalyzed performance for co-doped ZnS.