Be, O共掺杂实现p型AlN的第一性原理研究

基于密度泛函理论框架下的第一性原理平面波超软赝势方法,研究了掺杂和非掺杂AlN体系的晶格参数、 能带结构、总体态密度、分波态密度、差分电荷分布及电荷集居数.计算结果表明: Be掺杂AlN晶体能够在能隙中形成深受主能级,空穴载流子局域于价带顶, 而引入了激活施主O原子的Be, O共掺杂方法,能使受主能带变宽、非局域化特征明显. 同时,受主能级向低能方向移动,形成了浅受主能级, 从而提高了Be原子的掺杂浓度和系统的稳定性. Be, O共掺杂更有利于获得p型AlN.

First-principles study of Be, O codoped p-type AlN

By using the first-principles ultrasoft pseudo-potential approach of the plane wave based on the density functional theory, the electronic structures and their changes, the bandstructures, the densities of states, and the charge densities of pure Be-doped and Be-O codoped wurtzite AlN are calculated. The calculation results reveal that Be-doped wurtzite AlN gives rise to the formation of deep Be acceptor levels in the band gap and the carriers (hole) are localized near the top of the valence band, and the introduction of activated donor O atoms makes the acceptor level wider and the non-local characteristics distinctive, and can cause the primary level to shift toward the low energy, forming a shallow acceptor level, thereby enhancing the doping concentration of Be atoms and the stability of the system. Be, O co-doped p-type is more conducive to obtaining AlN.