Experimental determination of the top of the valence band in amorphous Al2O3 and γ-Al2O3

Abstract—Investigation of the energy distribution of occupied states in the valence band and determination of its upper level in films of amorphous Al2O3 and γ-Al2O3, synthesized by atomic layer deposition on a silicon substrate, was performed by X-ray photoelectron spectroscopy. The top of the valence gap in γ-Al2O3 was found to shift by 0.8 eV towards larger electron binding energies with respect to amorphous Al2O3.