Interfacial electronic structures of amorphous AI2O3/Z11O correlated with electrical properties of Al/Al2O3/ZnO metal-oxide-semiconductor structures

Abstract

Amorphous Al2O3 films have been deposited on single-crystal ZnO(1100) substrates by atomic layer deposition at 100°C. Interfacial electronic band structure of Al2O3/ZnO heterojunction has been characterized by X-ray photoelectron spectroscopy. Based on binding energies of core-levels and valence band maximum values, valence band offset has been found to be 0.8±0.2 eV for the Al2O 3/ZnO heterojunction. It shows type-I band configuration with conduction band offset of 2.5 ± 0.2 eV. The effect of surface treatment of ZnO using H2O2 on C-V properties of Al/ Al2O3/ZnO has been investigated. Al/ Al2O3/ZnO with the H2O2 treatment shows better electrical properties than the same structure without the H2O2 treatment. © 2012 The Surface Science Society of Japan.