In this letter, we describe the surface properties of GaN thin films grown on sapphire substrate by molecular beam epitaxy, as revealed by ultraviolet and x-ray photoelectron spectroscopic and Auger electron spectroscopic studies. The samples are seen to contain overlayer of native oxides, which are predominantly in the Ga2O3 form. Ammonia is shown to be a good etchant for these native oxides. Furthermore, we investigated the early stages of the reaction of monolayer Al with a GaN surface covered with native oxide. Aluminum reacts preferentially with the surface oxygen and leads to the formation of a mixture of oxides at the interface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.