We investigate p-type doping in ZnO prepared by the method of radical beam gettering epitaxy using NO gas as the oxygen source and nitrogen dopant. A narrow (0 0 2) peak is observed in the x-ray diffraction spectra, which indicates that the N-doped ZnO films are oriented along the c-axis. Secondary ion mass spectroscopy measurements demonstrate that N is incorporated into a ZnO film with a concentration of about 2.5 × 10 19 cm −3 . The hole concentration of the N-doped p-ZnO films was between 1.4 × 10 17 and 7.2 × 10 17 cm −3 , and the hole mobility was 0.9-1.2 cm 2 V −1 s −1 as demonstrated by Hall-effect measurements. The emission peak of 3.312 eV is observed in the photoluminescence spectra at 4.2 K of N-doped p-ZnO films, probably neutral acceptor bound excitons and the band of 3.24 eV, connected with a donor-acceptor pair recombination. The activation energy of the nitrogen acceptor was obtained by the temperature-dependent Hall-effect measurement, and is about 145 meV. The p-n heterojunctions ZnO/ZnSe were grown on the n-type ZnSe substrate, and have a turn-on voltage of about 3.5 V.

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