Interfacial Electronic Structures of Amorphous Al₂O₃/ZnO Correlated with Electrical Properties of Al/Al₂O₃/ZnO Metal-Oxide-Semiconductor Structures

Abstract

Amorphous Al₂O₃ films have been deposited on single-crystal ZnO(1-100) 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 Al₂O₃/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. [DOI: 10.1380/ejssnt.2012.165]