Cu,O共掺杂AlN晶体电子结构与光学性质研究

采用基于密度泛函理论的平面波超软赝势方法对纯Al N,Cu单掺杂以及Cu与O共掺杂Al N超胞进行了几何结构优化,计算了掺杂前后体系的晶格常数、能带结构、态密度与光学性质.结果表明:掺杂后晶格体积增大,系统能量下降;Cu掺入后Cu 3d电子与N 2p电子间有强烈的轨道杂化效应,Cu与O共掺后Cu和O之间的吸引作用克服了Cu原子之间的排斥作用,能够明显提高掺杂浓度和体系的稳定性.光学性质分析中,介电函数计算结果表明Cu与O共掺杂能改善Al N电子在低能区的光学跃迁特性,增强电子在可见光区的光学跃迁;复折射率计算结果显示Cu与O掺入后由于电磁波穿过不同的介质,导致折射率发生变化,体系对低频电磁波吸收增加.

Electronic structure and optical properties of Cu-O co-doped AlN

The geometry parameters, band structure, electronic density of states, and optical properties of AlN before and after being co-doped by Cu and O are investigated by the ultra-soft pseudo-potential plane wave based the density functional theory. The results show that the lattice volume increases and the total energy of the system decreases after doping. The Cu doping system makes Cu 3d electrons hybridize with its nearest neighbor N 2p electrons strongly. In the Cu-O co-doped system, Cu and O attract each other to overcome the repelling of acceptor Cu atoms, thereby increasing the doping concentration of Cu atoms and the stability of the system. Dielectric function calculation results show that Cu-O co-doping can improve the optical transition characteristics in low energy area of AlN electrons, and thus enhancing the optical transition of electrons in visible area. The complex refractive index calculation results indicate that Cu-O co-doped system increases the absorption of low frequency electromagnetic wave.