碱金属掺杂SnO2材料的电子结构和光学性质

First-principles Study on Electonic Structure of Alkali Metal Doped SnO2

摘要:

文章基于第一性原理研究了碱金属掺杂的SnO₂的能带结构以及态密度。研究结果表明:掺杂能够使能级增多,很好地调节带隙值。Li,Na,K,Rb掺杂的SnO₂材料,价带顶有能级穿过费米线,材料呈现出半导体特性。其中Rb掺杂使材料在费米面附近产生杂质能级。而Cs,Fr掺杂的SnO₂材料,价带顶向低能级方向移动,费米能级不再穿过价带,费米线附近出现轨道杂化,两者相比Fr掺杂使费米面附近能级分布更加离散。掺杂后SnO₂的反射率变化主要体现在可见光以及紫外区域,吸收边发生了红移,对实现SnO₂光催化起很大作用。

Abstract:

The band structures and electronic density of states of alkali metal doped SnO₂ systems were calculated by using the first-principles theory. The results show that with the increase of the energy levels of the doped SnO₂ system, the band gap can be adjusted well. The energy levels of the valence band top cross the Fermi line in the Li, Na, K, Rb doped SnO₂ system,and the system shows the characteristics of semiconductors. More energy levels were introduced to the Fermi line in Rb-doped SnO₂ system, because the valence band top moves to the low energy region in Cs, Fr doped SnO₂, the energy levels of the valence band top do not cross the Fermi line. The density of states of the doped system is hybrids near the Fermi line. Compared with the Cs-doped SnO₂, the energy levels in the Fr-doped SnO₂ disperse. The change of reflectivity of doped SnO₂ is mainly reflected in the visible and ultraviolet region, and the absorption edge is red shifted, which plays an important role in the realization of SnO₂ photocatalysis.