掺杂对二维SiC材料光电性质的影响

Effect of doping on photoelectric properties of two-dimensional SiC material

利用第一性原理赝势平面波方法计算了Si-C邻近元素(B、N、Al、P)掺杂二维SiC的几何结构、电子结构和光学性质。结果表明:掺杂后的二维SiC晶格常数(a、b)、键长及角度均发生了明显变化;同时,在禁带中引入了杂质能级,导带和价带均向低能方向发生了明显的移动,带隙发生变化,费米能级附近引入了杂质的2p及3p态电子。光学性质的计算表明:在低能端B、N、Al掺杂使二维SiC吸收电磁波的能力明显增强;静态介电常数增大而能量损失峰降低。以上结果说明可以根据需要利用B、N、Al、P掺杂来调制二维SiC材料的光电性质。

The first-principles pseudo-potential plane wave method is used to calcula te the geometric structure,electronic structure and optical properties of two-dimensional SiC doped by the adjacent e lements of C-Si （such as B,N,Al,P）. The results show that the doped two-dimensional SiC lattice constants （a,b）,bond length,and angle have changed significantly.In the forbidden band,the impurity levels are introduced,and bo th the conduction band and the valence band move to the lower energy direction,which make the band gap change.The 2p and 3p states of the impurity are introduced near the Fermi level.The calculation of optical properties shows tha t the ability to absorb electromagnetic waves of two-dimensional SiC has been enhanced obviously in the low energy rang e after （B,N,Al） doping.At the same time,the static dielectric constant increases and the peak of loss functio n decreases.The above results indicate that the optoelectronic properties of two-dimensional SiC can be modulated by d oping B,N,Al,P as required.