Engineering ZnO/GaN interfaces for tunneling ohmic contacts to GaN

摘要

We have investigated two approaches for the fabrication of thin ZnO films: sputter deposition from the ZnO target and thermal oxidation of vacuum deposited Zn.The microstructure and electronic properties after consecutive steps of the formation of n-ZnO/p-GaN contacts have been studied using electron transmission microscopy and x-ray photoelectron spectroscopy.We have achieved ohmic contacts by Zn oxidation and explain their ohmic behaviour in terms of a tunnel n~+-ZnO-p-GaN junction.