Mn,Fe,Co掺杂GaAs电子结构与光学性质的第一性原理研究

First principles study on electronic structures and optical properties of Mn,Fe and Co doped GaAs

采用基于密度泛函理论的平面波超软赝势方法对本征GaAs以及3d过渡金属Mn、Fe、Co单掺杂GaAs晶体的电子结构及其光学性质进行理论计算以及对比研究.计算结果表明:能带结构中三种掺杂体系均引入新的能级,能带条数增多,导带底与价带底顶向深能级移动,带隙减小;费米能级附近出现了杂质能级,导致掺杂体系光子能量位于0时介电函数虚部便有所响应,掺杂体系相较于本征体系的静介电常数有所提升;Mn、Fe、Co三种掺杂体系相较于本征体系在红外以及远红外区域吸收系数得到了明显的提升,其中Fe掺杂GaAs的光催化特性最好.

The electronic structures and optical properties of intrinsic GaAs and 3d transition metal Mn,Fe and Co single doped GaAs crystals are calculated and compared by using the plane wave ultrasoft pseudopotential method based on density functional theory.The results show that the three doped systems introduce new energy levels,the number of energy bands increases,the bottom of conduction band and the top of valence band move to deep level,and the band gap decreases;The impurity level appears near the Fermi level,When the photon energy of the doped system is at 0,the imaginary part of the dielectric function will respond,and the static permittivity of the doped system is higher than that of the intrinsic system;Compared with the intrinsic system,the absorption coefficients of Mn,Fe and Co doped systems in infrared and far-infrared regions are significantly improved,Among them,Fe doped GaAs has the best photocatalytic properties.