Roles of hydrogen and nitrogen in p-type doping of ZnO

N-doped ZnO thin films were prepared by atmospheric pressure mist chemical vapor deposition. The behaviors of H and N impurities were systematically studied, and a hydrogen-assisted nitrogen-doping mechanism was proposed to produce p-type ZnO. The H and N concentrations showed a linear correlation in as-grown samples. The p-type conductivity was realized by rapid thermal annealing in N2 environment, with the hole concentrations typically of 1017 cm−3 at 475–500 °C. In this temperature window the dissociated hydrogen showed significant outdiffusion, while the nitrogen still remained stable in ZnO and behaved as effective acceptors resulting in good p-type conductivity.