Electronic structures and optical properties of substitutional and interstitial N-doped ZnO

In this paper, the formation energies, electronic structures and optical properties of substitutional and interstitial N-doped ZnO were calculated by density functional theory (DFT). The results show that the N atom prefers to octahedral interstitial site because of low formation energy. The p-type ZnO is obtained by N doping, and N atom at interstitial site can narrow band gap width obviously, which will improve the solar light absorption and utilization. In the energy region of visible light, the N atom at interstitial site has a good absorption spectrum of visible light and results in redshift significantly, which is consistent with the band gap width change regulation. (authors)