Effect of different valence cation vacancies and interstitial H on the photocatalytic performance of two-dimensional GaN:(O/C)

Abstract

The effects of point defects on the physical properties of gallium nitride (GaN) monolayer surfaces have been widely reported in experimental and theoretical computational studies. However, the effects of different valence states of VGa and O/C and interstitial H co-doping on the photocatalytic properties of two-dimensional (2D) GaN surfaces have been rarely reported. Experimental studies on GaN based on Metal Organic Chemical Vapor Deposition and Vacuum Coating methods often overlook the unintentional existence of interstitial H in Ga vacancy. The structure, stability, and main affecting factors of the photocatalytic performance of Ga35MHiN35 (VGa3−/VGa2−/VGa1−/VGa0) (M = O/C) 2D surfaces were investigated to solve the present problem by using a generalized gradient approximation of the plane wave supersoft pseudopotential + U in the framework of density generalization theory. Results show that the 2D surface of Ga35MHiN35(VGa3−/VGa2−/VGa1−/VGa0) (M = O/C) is more stable under N-rich conditions, and the surface is more easily doped. Analysis of the electric dipole moment, effective mass, optical properties, and redox reactions of the doped surfaces reveals that the 2D surface of Ga35CHiN35 (VGa3−) has the best carrier activity, the best absorption spectral redshift, the longest carrier lifetime, and the strongest redox ability. Therefore, the 2D surface of Ga35CHiN35(VGa3−) is best as a photocatalyst. This work facilitates the preparation of new 2D GaN photocatalysts.