第一性原理研究Be-S共掺杂AlN纳米片的电子结构和光学性质

基于密度泛函理论体系下广义梯度近似(GGA),利用第一性原理方法计算了Be替代Al、S替代N和Be-S共掺杂对氮化铝纳米片的电子结构和光学性质的影响.计算结果表明,掺杂改变了氮化铝纳米片的带隙,但仍显示半导体特性. Be掺杂类型对氮化铝纳米片的晶体结构影响不大,而S掺杂和Be-S共掺杂都使得氮化铝纳米片有不同程度的弯曲.同时Be-S共掺杂中S原子起到激活受主杂质Be原子的作用,使得受主能级向低能方向移动.共掺杂比单掺杂具有更高的受主原子浓度,并减小局域化程度.光学性质也发生较大改变:S原子掺杂氮化铝纳米片的介电函数虚部出现第二介电峰,Be掺杂和Be-S共掺杂使得损失谱的能量区间有所展宽,峰值降低并向高能区移动.

First principles study of the electronic structure and optical properties of Be-S codoping AlN nanosheets

The influence of Be instead of Al, S instead of N and Be-S codoping on the electronic structure and optical properties of aluminum nitride nanosheets have been investigated by first-principles method based on the density function theory with the generalized gradient approximation. The calculation results show that the doped changes the band gap of the aluminum nitride nanosheet, but still shows the semiconductor characteristics. The type of Be-doped has a little effect on the crystal structure of aluminum nitride nanosheet, while S-doped and Be-S codoping make aluminum nitride nanosheets have different degrees of bending. At the same time, the S atom in the Be-S codoping acts to activate the acceptor impurity Be atom, so that the acceptor level shifts toward the low energy direction. Codoping has a higher acceptor atom concentration than single doped and reduces the degree of localization. The optical properties also changed greatly: the second dielectric peak appeared in the imaginary part of the dielectric function of the S atom doped aluminum nitride nanosheet, and the Be doped and Be-S codoping broadened the energy range of the loss spectrum. the peak decreases and moves to the high energy zone.