ELECTRONIC STRUCTURE AND OPTICAL ABSORPTION OF N-DOPED ZnO

Abstract

The plane-wave pseudopotential method, based on density functional theory (DFT), has been used to calculate the electronic and optical properties of pure ZnO and N-doped ZnO . The results of density of states (DOS) indicate that the band gap of N-doped ZnO decreases due to the increase of p states in the valence band. Meanwhile, the results of the imaginary part of dielectric function ε2(ω) reveal that the optical transition between O 2p states in the highest valence band and Zn 4s states in the lowest conduction band shifts to the low energy range due to N doping. The optical band gap of ZnO decreases from 3.2 to 2.2 eV after N doping.