Comment on “Low-resistance ohmic contacts to p-type GaN achieved by the oxidation of Ni∕Au films” [J. Appl. Phys. 86, 4491 (1999)

Abstract

A very low barrier height (∼0.055V) at the p-GaN side in energy band diagram of p-NiO∕p-GaN interface was obtained in the paper: “low-resistance ohmic contacts to p-type GaN achieved by the oxidation of Ni∕Au films.” They contributed the low contact resistance to the low energy barrier height for holes. We indicate the mistake of their calculation and obtain a barrier height of 2.28V and a notch of 0.19V on the p-GaN side and the p-NiO side, respectively, in this comment.