Recent advances in NiO/Ga2O3 heterojunctions for power electronics

Abstract Beta gallium oxide ( β -Ga 2 O 3 ) has attracted significant attention for applications in power electronics due to its ultra-wide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga’s figures of merit (BFOM) of more than 3000. Though β -Ga 2 O 3 possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β -Ga 2 O 3 -based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide (NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/ β -Ga 2 O 3 heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/ β -Ga 2 O 3 heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/ β -Ga 2 O 3 heterojunctions are discussed. Various device architectures, including the NiO/ β -Ga 2 O 3 heterojunction pn diodes (HJDs), junction barrier Schottky (JBS) diodes, and junction field effect transistors (JFET), as well as the edge terminations and super-junctions based on the NiO/ β -Ga 2 O 3 heterojunction, are described.