【Epitaxy Papers】Heteroepitaxial integration of α-Ga₂O₃/p-NiO by mist-CVD for solar-blind UV detection

      Researchers from Central South University have published a dissertation titled " Heteroepitaxial integration of α-Ga₂O₃/p-NiO by mist-CVD for solar-blind UV detection " in Journal of Applied Physics

Abstract

      Solar-blind ultraviolet (SBUV) photodetection is critically demanded in military and civil fields thanks to its near-zero background radiation. Gallium oxide (Ga₂O₃) emerges as an ideal wide-bandgap semiconductor for SBUV and power devices thanks to its suitable bandgap and compatibility with substrates. Up to now, the lack of stable p-type Ga₂O₃ has become a bottleneck, restricting its application. Consequently, p–n heterojunction formation is one possible solution, where p-type nickel oxide appears as a promising p-type semiconductor. Here, we employ mist chemical vapor deposition technology to demonstrate epitaxial integration of single-crystal α-Ga₂O₃/NiO heterojunctions on c-plane sapphire, featuring a distinct interface with an epitaxial relationship of α-Al₂O₃(0006) || α-Ga₂O₃(0006) || NiO(111). The as-grown Li⁺-doped NiO film shows a high hole mobility (88.32 cm²/V s) and low resistivity (0.09 Ω cm) and exhibits a type-II band alignment with α-Ga₂O₃, consequently enabling efficient carrier separation. The fabricated α-Ga₂O₃/NiO p–n junction photodetector exhibits rectification effects and self-powered detection capability, achieving high-performance UV detection with a responsivity of 43.86 A/W, detectivity of 1.64 × 10¹² Jones, rejection ratio of 177.3, and fast response (17/16 ms). This work demonstrates a low-cost epitaxial approach to realize high-quality α-Ga₂O₃/NiO p–n heterojunction integration for fast UV detection applications.

DOI：

https://doi.org/10.1063/5.0317497