Recent advances in NiO/Ga2O3 heterojunctions for power electronics

Beta gallium oxide(β-Ga2O3) has attracted significant attention for applications in power electronics due to its ultrawide 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-Ga2O3possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga2O3-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-Ga2O3heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga2O3heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga2O3heterojunctions are discussed. Various device architectures, including the NiO/β-Ga2O3heterojunction 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-Ga2O3heterojunction, are described.