Ag掺杂ZnO/GaN异质结可见光吸收特性的第一性原理

ZnO/GaN异质结带隙宽度较宽，制约了对可见光的吸收。为研究Ag对ZnO/GaN异质结可见光吸收的影响，在(1-100)非极性面上构建GaN/ZnO异质结，并用Ag分别取代不同位置的Zn和Ga原子，采用第一性原理计算Ag掺杂对ZnO/GaN异质结稳定性、电子结构、光学性质和带边位置的影响。研究结果表明：Ag掺杂ZnO/GaN异质结形成能为负值，结构稳定；Ag置换Zn和Ga使带隙宽度由2.93 eV分别减小至2.7 eV和2.3 eV，吸收系数和光电导产生红移，有利于可见光的吸收，Ag掺杂ZnO/GaN异质结具有良好的光催化活性。

First principle on visible light absorption characteristics of Ag doped ZnO/GaN heterojunction

The band gap width of ZnO/GaN heterojunction is large, which restricts absorption of visible light. In order to study the effects of Ag on the visible light absorption of ZnO/GaN heterojunction, GaN/ZnO heterojunction is constructed on the (1-100) nonpolar plane, and Ag is utilized to replace Zn and Ga atoms at different positions, respectively. Then, the influence of Ag doping on the stability, electronic structure, optical properties and band edge position of ZnO/GaN heterojunction is calculated by first principle. The results reveal that the system of Ag doped ZnO/GaN heterojunction is stable because of the negative formation energy. For Ag replaced Zn and Ga, the band gap width decreases from 2.93 eV to 2.7 eV and 2.3 eV, which results in red shift of absorption coefficient as well as photoconductivity, and is beneficial to the absorption of visible light. Finally, Ag doped ZnO/GaN heterojunction has excellent photocatalytic activity.