Ⅲ族元素掺杂对SnO2电子结构及电学性能的影响

采用密度泛函理论研究了Ⅲ族元素掺杂对SnO₂电子结构及电学性能的影响.态密度分析结果表明，以替代位存在的Ⅲ族杂质均使SnO₂的费米能级明显向低能态方向移动，使得价带顶不完全填满，因此在SnO₂中均充当受主作用.部分态密度分析结果表明，相对于掺Al的SnO₂，Ⅲ族元素中的Ga及In对费米能级附近态密度贡献较大，其主要贡献来自Ga3d态或In4d态，这预示着在SnO₂中掺Ga或In能实现更好的p型掺杂效果.电离能计算结果进一步表明，在Al，Ga及In三种元素中，替位In有最小的电离能(0.06 eV)，这说明其在SnO₂中能形成最浅的受主能级，因而在同等掺杂情况下，可引入最高浓度的空穴，从而实现最佳的p型掺杂效果. 关键词： 密度泛函理论 2')" href="#">SnO₂ Ⅲ族元素掺杂 电子结构

The effect of Ⅲ-family element doping on electronic structures and electrical characteristics of SnO2

The electronic structures of SnO₂ doped by Al, Ga and In were examined using density functional theory. Density of states (DOSs) calculation showed that the Fermi levels of all Ⅲ-family doped SnO₂ systems shift to lower energy and therefore a partially occupied valence band was formed near the valence maxima, which indicates that substitional Ⅲ-group atoms act as acceptors in SnO₂. Partial DOSs indicates that compared with substitional Al, substitional Ga or substitional In contribute much more because of the d states, Ga3d or In4d, which suggests that Ga and In is better than Al for p-type doping of SnO₂. Ionization energy calculation further indicates that,of the substitional In, Ga and Al, substitional In has the smallest ionization energy of 0.06 eV, which means that substitional In gives the shallowest acceptor level in SnO₂, and thus the highest hole concentration at the same doping concentrations.