High-performance type-I Sn-doped-Ga2O3/SnSe2 heterojunction photodetectors enabled by Fowler–Nordheim tunneling

Gallium oxide (Ga2O3) is renowned for its exceptional physical and chemical properties, making it an ideal material for solar-blind photodetectors. In this study, Sn-doped-Ga2O3 microwires (MWs) were utilized to fabricate a type-I heterojunction photodetector with SnSe2. The Sn-doped-Ga2O3 MW/SnSe2 hybrid van der Waals heterojunction exhibits both direct tunneling and Fowler–Nordheim tunneling under positive voltages. By exploiting the Fowler–Nordheim tunneling mechanism at a 6 V bias, the device demonstrates outstanding performance under 254 nm illumination, achieving a rectification ratio of 104–105, an ultralow dark current of 0.11 pA, a responsivity of 81.82 A/W, a detectivity of 7.79 × 1014 Jones, and an exceptionally high external quantum efficiency of 4 × 104%. These impressive characteristics make the heterojunction photodetector highly suitable for high-quality imaging applications. This research offers a promising processing solution for Ga2O3-based optoelectronic devices, further extending their potential for versatile solar-blind detection and imaging applications.