Investigation of Energy Band at Atomic-Layer-Deposited ZnO/β-Ga2O3 ( 2¯01 $$ \overline{2}01 $$) Heterojunctions

Abstract

Abstract The energy band alignment of ZnO/β-Ga2O3 ( 2¯01 $$ \overline{2}01 $$) heterojunction was characterized by X-ray photoelectron spectroscopy (XPS). The ZnO films were grown by using atomic layer deposition at various temperatures. A type-I band alignment was identified for all the ZnO/β-Ga2O3 heterojunctions. The conduction (valence) band offset varied from 1.26 (0.20) eV to 1.47 (0.01) eV with the growth temperature increasing from 150 to 250 °C. The increased conduction band offset with temperature is mainly contributed by Zn interstitials in ZnO film. In the meanwhile, the acceptor-type complex defect Vzn + OH could account for the reduced valence band offset. These findings will facilitate the design and physical analysis of ZnO/β-Ga2O3 relevant electronic devices.

Keywords

• β-Ga2O3
• Contacts
• ZnO
• ALD