Ce/GaN(0001) interfacial formation and electronic properties

Abstract

X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy electron diffraction have been used to study the growth, interfacial reaction, and Fermi level movement of Ce on a n-type GaN(0001)-(1×1) surface. The results demonstrate that Ce grows in a layer-by-layer-like mode and reacts with the substrate at the interface, leading to formation of metallic Ga at room temperature. With increasing Ce coverage, a downward Fermi level movement is observed, and the resultant Schottky barrier height is 1.3 eV. Annealing promotes further diffusion and thus interfacial Ce–Ga exchange reaction.