Y,Zr,Nb掺杂SnO_2电子结构的第一性原理研究

Study on electronic structures of Y,Zr and Nb doped SnO_2 by first principles

本文基于第一性原理方法研究了Y,Zr,Nb在Sn位掺杂SnO_2的键长变化、稳定性、能带结构以及态密度.结果表明:Y,Zr,Nb在Sn位掺杂SnO_2使附近的键长发生改变,改变量最大是Y掺杂SnO_2体系;掺杂体系的杂质替换能都为负值,表明体系为稳定结构;掺杂使SnO_2能级增多,能较好的调节带隙值;而Y掺杂SnO_2体系价带顶端有一条能级越过了费米线表明该体系呈现出半导体的特征;同时,Y,Zr,Nb掺杂SnO_2使导带底端的能级出现分离;在低能区的态密度仍主要由Sn、O的s轨道贡献;在高能区态密度的掺杂体系出现sp杂化的现象; Zr掺杂SnO_2的态密度能量向低能区移动.

In this work,band structures and densities of states of yttrium,zirconium and niobium doped SnO 2 are studied by first principles method.Comparing with the pure SnO 2,the bond lengths of the doped SnO 2 for these impurities at Sn positions are changed.The largest change is the Y doped SnO 2 system.All doped structures are stable,because the substitution energies of impurities can all be negative.With the increase of the energy level of SnO 2,the band gap can be adjusted well.An energy level crosses the Fermi line in the Y doped SnO 2 system,it shows that the system has the characteristics of semiconductors.There is a separation of energy levels at the bottom of the guide band in the Y,Zr and Nb doped SnO 2 systems.The density of states is still mainly contributed by the s orbits of Sn and O in the low energy region.The density of states of the doped system is sp hybrids.The density of state moves to the low energy region in the Zr doped SnO 2.