Investigation on the p-type formation mechanism of nitrogen ion implanted ZnO thin films induced by rapid thermal annealing

N-doped p-type zinc oxide (ZnO) thin films were prepared by rapid thermal annealing (RTA) of nitrogen ion implanted high quality ZnO epitaxial layers. Annealing at 900 degrees C in a nitrogen atmosphere leads to the conversion of conductivity from n to p-type with a hole concentration of 9.60x 10(17) cm(-3), which is reflected in photoluminescence spectra. To reveal the thermal activation and doping mechanism of this film, the samples were also analyzed by Raman scattering and X-ray photoelectron spectroscopy. The results indicate that elimination of the Zn-i related shallow donors and the formation of shallow acceptor complex N-o-V-Zn account for the stable p-type conductivity of N-doped ZnO. The shallow acceptor state is calculated at 0.161 eV above the valence band edge. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement