ZnO掺杂对GaN/ZnO固溶体能带结构的影响及其光催化性能

This study investigates the effect of different concentrations of ZnO doping on the energy band structure of GaN/ZnO solid solutions. By calculating the band structures of 350 GaN/ZnO solid solution structures and measuring the corresponding bandgap sizes, it was found that as the ZnO content increases, the bandgap of the solid solution structure first rapidly decreases, stabilizes at around 0.05 eV, and then slightly increases to 0.2 eV when the ZnO content is high. The decrease in bandgap is mainly attributed to the increase in Zn-N bonds. The solid solution can achieve continuous bandgap control by increasing the ZnO content. The study also analyzed the band structures and density of states of GaN and ZnO intrinsic semiconductors and selected three representative structures for analysis. The study found that the repulsion between the N 2p and Zn 3d orbitals causes the valence band position to rise and the conduction band bottom level to increase, resulting in a decrease in the bandgap. The study also found that solid solutions with high ZnO concentrations have a larger effective mass, which limits the diffusion of photogenerated carriers and reduces their mobility. The study further explored the optical absorption performance of GaN/ZnO solid solutions with ZnO doping concentrations below 25%, and found that increasing the ZnO concentration significantly enhances the visible light response, resulting in an absorption peak in the visible light region and a red shift to a certain extent. This phenomenon is attributed to the introduction of a mid-gap state, which reduces the bandgap and increases the efficiency of visible light utilization. Based on these results and theoretical analysis, it can be concluded that GaN/ZnO solid solution catalysts can effectively improve the efficiency and performance of visible light photocatalysis for water decomposition.