The electrical properties of Ni/Au and Au contacts on p-type GaN (P-GaN) were investigated in this study. From the experimental result, it is suggested that the current-voltage characteristic of Au/Ni/p-GaN is better than that of Au/p-GaN. The secondary-ion mass spectroscopy measurements revealed that hydrogen is effectively removed from the p-GaN layer by the existence of the Ni film. These results suggest that a Ni film of Au/Ni/p-GaN significantly enhances hydrogen desorption from the p-GaN film, which leads to an increase in the hole concentration, the occurrence of the tunneling transmission for holes at the interface, and the improvement of electrical properties of Au/Ni/p-GaN. (C) 2005 American Vacuum Society.