Ru/GaN(0001) interface properties

Abstract

We report the results of our studies of ruthenium layer structures adsorbed on GaN(0001). Ruthenium was evaporated at room temperature under ultrahigh vacuum conditions onto n-type GaN substrates epitaxially grown on sapphire. When X-ray photoelectron spectroscopy confirmed the presence of Ru bonds in the deposited adlayer, the ultraviolet photoelectron spectroscopy shown a peak at the Fermi level as well as lines originating from ruthenium. The height of the Schottky barrier was calculated based on the data measured by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy and amounts to 1.5 eV. The work function of Ru adlayer is 4.4 eV, while the electron affinity of n-GaN(0001) substrate equals 3.4 eV.