Investigation of Energy Band at Atomic-Layer-Deposited ZnO/β-Ga 2 O 3 ([Formula: see text]) Heterojunctions

The energy band alignment of ZnO/β-Ga O ([Formula: see text]) 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-Ga O 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 V + OH could account for the reduced valence band offset. These findings will facilitate the design and physical analysis of ZnO/β-Ga O relevant electronic devices.