β -Ga 2 O 3 -based heterojunctions: Effects of growth orientation and alloying on electronic properties

We investigate the effects of alloying and growth orientation on the electronic properties of the ultrawide bandgap semiconductor β -Ga 2 O 3 and pseudomorphic ( Al x Ga 1 − x ) 2 O 3 alloy heterojunctions. Band offsets are computed from first principles using density functional theory with the Heyd-Scuseria-Ernzerhof hybrid functional for different aluminum concentrations and four growth orientations, namely, (100)B, (010), (001)B, and ( 2 ¯ 01 ). Significant variations are found and ascribed to the strained pseudomorphic alloys. The values of the band offsets are fed into technology computer-aided design (TCAD) models of Schottky barrier diodes (SBD). I - V and C - V characteristics from the TCAD models show reasonable agreement with recent experimental measurements in the forward bias region. Discrepancies in the negative bias region are expected due to the ideality of the Schottky junctions considered in this study. Our findings underscore the critical role of growth orientation and strain in the accurate modeling of β -Ga 2 O 3 -based SBD.