Effect of nitrogen doping on electronic and optical properties of ZnO sheet: DFT+U study

Structural, optical and electronic properties of bulk and two-dimensional (2D) nanostructure of pure and N-doped ZnO have been investigated using density functional theory and the Hubbard U (DFT + Ud + Up) method. Here, we considered four models of graphene like pure and N-doped ZnO (one layer and two layers) and compared them to bulk ZnO. This study evaluates the influence of Hubbard U parameter on p-orbital electrons of nitrogen (Up,N). Our optical and electronic analyses of Up,N = 7eV show nitrogen is a deep acceptor for bulk N-doped ZnO, which is in good agreement with some theoretical and experimental reports. Results show the existence of N atoms cannot lead to hole conductivity in ZnO bulk and graphene like layers of N-doped ZnO.