Sn、Cu掺杂的β-Ga₂O₃能带的理论计算

Theoretical Calculation of Energy Band on β-Ga₂O₃ Doped with Sn and Cu elements

摘要: 本文基于MS 2018软件，采用密度泛函第一性原理方法，利用平面波超软赝势计算了β-Ga₂O₃超胞掺杂不同含量Sn、Cu元素后的能带结构、态密度和分波态密度变化特性。研究发现，在本征半导体β-Ga₂O₃超胞中进行少量的Sn、Cu元素掺杂均可减小β-Ga₂O₃的禁带宽度，增强其导电特性。少量Sn掺杂后，β-Ga₂O₃的费米能级更接近导带，表现出更明显的n型导电特性，且其费米面附近的态密度明显增加。而少量Cu掺杂后，价带上部还出现了浅受主能级，导致β-Ga₂O₃的费米能级更接近其价带，具有明显的p型导电特性。对比研究发现，掺杂浓度越高，费米面附近的态密度增加效果就越强，这更有利于β-Ga₂O₃半导体用于制备各类异质结晶体管和光电器件领域中。

Abstract: Based on plane-wave ultra-soft pseudopotential model in the MS 2018 software, the energy band structure, density of states and partial density of the intrinsic β-Ga₂O₃ and β-Ga₂O₃ doped with different contents of Sn and Cu elements were calculated by using the first-principles calculation method. The results show that a small amount of substituted Sn and Cu atoms doping in the intrinsic β-Ga₂O₃ supercell lattice structure can reduce the bandgap width and the conductivity of β-Ga₂O₃ can be improved. Doped with a small amount of Sn elements, the Fermi energy level of Sn/β-Ga₂O₃ moves forward to the conduction band bottom, showing more obvious n-type conductivity, and the density of states near the Fermi energy level increases obviously. However, doped with a small amount of Cu elements, the Fermi energy level of Cu/β-Ga₂O₃ is closer to the top of the valence band and the shallow donor impurity energy level is introduced into the top of the valence band, showing an obvious p-type conductivity. All the calculation results indicate that the higher the doping concentration is, the stronger the effect of increasing the density of states near the Fermi energy level is, which is more favorable for β-Ga₂O₃ semiconductor to be used in the preparation of various heterojunction transistors and optoelectronic devices.