Preparation of p-NiO-SiC heterojunction on 4H-SiC substrate

摘要

In this work, nickel oxide (NiO) film was prepared on 4H-SiC (0001) by radio frequency magnetron sputtering to form NiO/4H-SiC p-n heterojunction for the first time. XRD results indicated NiO film had (200), (220), and (020) oriented crystal structures and SEM results showed homogeneous distribution of small grains on 4H-SiC substrate. The optical band gap for NiO was calculated as 3.75 eV by UV-visible absorption spectra. The current-voltage characteristic of the NiO/4H-SiC p-n heterojunction showed a typical rectification behavior with a turn-on voltage of 1.4 V. The discontinuities of the valence band edge and the conduction band edge were estimated to be 1.15 eV and 1.64 eV, respectively. The differences in barrier heights for holes and electrons indicated an improved hole injection capacity of NiO/4H-SiC p-n heterojunction.