Polarization-engineered electron transport in <i>β</i> -Ga2O3/SiC heterojunctions: Atomic-scale modulation via SiC polymorphic selection

Abstract

β-Ga2O3/SiC heterojunction has high potential to be used in high power electronics and optoelectronic devices, yet their performance is critically governed by their interfacial band properties. Here, we systematically investigate the band alignment and electron transport of β-Ga2O3/SiC heterojunctions with different SiC polytypes (2H-, 4H-, 6H-, and 3C-SiC). Precise calculations of band alignment are performed, accompanied by detailed analyses of charge transport and band bending mechanisms. Owing to the identical valence band maximum positions across SiC polytypes, all heterojunctions exhibit similar valence band offsets within 1.99–2.03 eV at the interface, while the differences in their bandgaps result in distinct conduction band offsets. Spontaneous polarization and mismatch-induced piezoelectric polarization collectively drive band bending within the SiC region. For hexagonal SiC polytypes, downward band bending occurs from the interface into the bulk, with the bending magnitude decreasing as hexagonal symmetry reduces. In contrast, 3C-SiC shows inversely upward bending owing to the dominance of piezoelectric polarization. Finally, we propose applicable material selection and doping strategies for specific device applications. This work provides theoretical guidance for the collaborative design of β-Ga2O3/SiC heterojunction-based devices.