Passivation of Surface States in GaN by NiO Particles

1 min read · Thu, Jan 27 2022

we characterized the surface states in GaN by EIS analyses and demonstrated that NiO particles deposited directly on GaN passivate them. These surface states are generated by the electronic bindings of superficial Ga atoms, and the interaction of those atoms with NiO modifies its chemical structure, as demonstrated by XPS measurements.

GaN and NiO/GaN electrodes were characterized by impedance spectroscopy measurements in 0.1 M NaOH. We observed the suppression of the surface states capacitance due to the modification of the chemical state of superficial Ga atoms by NiO. This result suggests that the carriers involved in the photocorrosion of GaN in alkaline conditions originate in its surface states. In addition, we characterized the epitaxial relationship between the NiO particles deposited on GaN by transmission electron microscopy, finding the NiO {111} || GaN {0002} and NiO || GaN symmetry constraints.