Band alignment and electronic structure of β-Ga2O3 (−201) grown on Si- and C-faces of 4H–SiC substrates

Abstract

In this manuscript, epitaxial beta-Ga2O3 films were prepared on 4H–SiC substrates via low-pressure chemical vapor deposition. β-Ga2O3 thin films with a (−201) preferred orientation were formed on (Si-face) 4H–SiC (0001) and (C-face) 4H–SiC (000‾1) with surface roughness values of 2.92 and 3.97 nm, respectively. The band alignments of both Si- and C-faces of β-Ga2O3/4H–SiC heterojunctions were investigated via X-ray photoelectron spectroscopy. The bandgaps for Si- and C-faces of β-Ga2O3 were measured to be 4.92eV and 4.79eV, respectively. The band diagrams revealed that the Si- and C-faces of β-Ga2O3/4H–SiC heterojunctions are straddling-gap (type I). The valence band offsets were determined to be 1.46 ± 0.05 and 1.19 ± 0.05 eV for Si- and C-faces, respectively. The conduction band offsets were shown to be 0.20 ± 0.05 eV for the Si-face and 0.34 ± 0.05 eV for the C-face. The comprehensively evaluation of the band offsets for Si- and C-faces of β-Ga2O3/4H–SiC heterojunctions have significant meaning for the design and optimization of electronic devices.