Construction of ZnO/GaN in-plane heterojunction with different contacted modes and vacancy defects for improving magnetic and adsorption properties

ZnO/GaN in-plane heterojunction with three contacted modes (Zn-N, Ga-O and both Zn-N and Ga-O, named He1, He2 and He3, respectively) is constructed. At the same time, the vacancy defects (VZn, VN, VGa and VO) are introduced at the interface of the in-plane heterojunction. Their electric, magnetic and adsorption properties with vacancy defects are analyzed based on density function theory (DFT). After constructing the heterojunction, the effective mass of holes obviously increases and leads to higher separation efficiency between electrons and holes. Band structures show that VZn and VGa change the magnetism of He3 and total magnetic moment (M) are 1.69 μB and 2.73 μB, respectively. He3 exhibits semiconducting conductivity with VZn and semi-metallic conductivity with VGa. In order to explore the application in gas sensing field, the electric and adsorption characteristics of He3 (with VZn and VGa) for CO2, SO2 and NO2 gas molecules are combined to analysis. Ead of the He3 for SO2 and NO2 is higher than CO2 adsorption. In addition, the magnetic properties of He3 (with VZn and VGa) change drastically after adsorbing SO2 and NO2, which proves that He3 is more sensitive to SO2 and NO2 than CO2. These results demonstrate that He3 not only exhibits unique electrical and magnetic properties, but also has potential applications in SO2 and NO2 gas sensors.