Epitaxial growth and band alignment properties of NiO/GaN heterojunction for light emitting diode applications

摘要

Epitaxial NiO layers have been grown on GaN templates with the out-of-plane and in-plane epitaxial relationship of [111]_(NiO) ‖ [0001]_(GaN) and [-110]_(NiO) || [-12-10]_(GaN), respectively. The epitaxial NiO layer is found to have two domain structures oriented along the [111] direction with an in-plane rotation of ~60° with respect to each other. A type-II band alignment with valence and conduction band offset values of 1.4 ± 0.1 eV and 1.9 ± 0.1 eV, respectively, has been obtained from photoemission spectroscopy. The determined band offset values and band alignment are helpful to determine charge transport and recombination mechanisms in optoelectronic devices based on the NiO/GaN heterojunction.