Effect of annealing on the surface characteristics of α-Al2O3(0001) probed by XPS

Abstract

α-Al2O3(0001) is a technologically important metal oxide substrate used in current solid state electronic devices. This report presents the effect of heat treatment on the surface electronic structure characteristics of α-Al2O3(0001) substrates examined by x-ray photoelectron spectroscopy. Survey spectra, O 1s, Al 2p, Al 2s core levels, and valence band spectra are presented for the as received, vacuum annealed, and oxygen annealed substrates. Annealing removes various contaminants such as C, Zn, and OH groups from the surface, and a sharp (1 × 1) low energy electron diffraction pattern confirms the ordered hexagonal periodicity of the surface. No substantial differences in the valence band spectra are observed due to annealing and suggest that the (1 × 1) surface characteristics of α-Al2O3(0001) are preserved during the surface cleaning procedures.