AlZn_(2n-1)O_(2n)电子结构与光学性质研究

Electronic Structure and Optical Properties of AlZn_(2n-1)O_(2n)

采用基于密度泛函理论（DFT）的总体能量平面波超软赝势法,电子交换关联能结合广义梯度近似（GGA）PW91形式,对Al原子掺杂不同超晶胞ZnO∶AlZn2n-1O2n（n=4,8,16和32）进行几何优化,分析比较了掺杂模型的电子结构及光学性质。结果表明,Al置换Zn位置掺杂容易,随着掺杂摩尔比例（Al∶ZnO）的减小,杂质元素对超晶胞晶格畸变程度减弱,Al和基体ZnO的原子数配比直接影响导电性能。光学性质计算发现,掺杂Al对紫外光波段（100~400nm）影响明显,随着摩尔比例（Al∶ZnO）减少,掺杂材料吸收系数下降,本征吸收边存在紫外光很窄波段内,电子跃迁的轨道能级主要集中于紫外光波段。

In this article,optical and electronic properties of AlZn2n-1O2n were studied according to DFT theory.The GGA in the form of PW91 and ultra-soft pseudo potential（USPP） were conbined with the exchange correction energy.The lattice constant and optical properties of these structures were calculated and compared with the experiments and previous theoretical works.It reavealed that Al replaces Zn is easy and the inpurities may have less impact on the degree of supercell lattice distortio with Al∶ZnO minishing and the ratio of Al and ZnO atom directly influences the ability of conductivity.And the doping Al affection is apparent in the UV band（100～400 nm） in the calculation of optical proporties.With the mole ratio of Al∶ZnO decreasing,the absorption coefficient falls and the intrinsic absorption edge locates in a narrow band of ultraviolet light,which shows that the orbital energies of electronic transition concentrate on the ultra-violet band.