Boosted photoresponse and broadened spectral range of GaN through SnSe2/GaN heterostructure

Abstract

Among two-dimensional materials, SnSe₂ is the most suitable material for integration with GaN for broadband absorption and self-powered operation due to its unique bandgap. When integrated with GaN, the resulting heterostructure can suppress dark current while maintaining high photocurrent levels. Recent advancements in self-powered broadband photodetectors have shown significant progress, but the photo-sensing capabilities of SnSe₂/GaN heterojunction remain unexplored. This work synthesized a SnSe₂/GaN heterostructure via a radio frequency sputtering technique and fabricated a metal-semiconductor-metal type device design using thermal evaporation. The sputtered SnSe₂ film generates an intrinsic electric field, enabling self-powered functionality. The developed SnSe₂/GaN heterostructure photodetector demonstrated an enhanced photoresponse and expanded spectral range of GaN but also exhibited a self-powered response even for weak optical signals. The device exhibited a responsivity of 3794 mA W^-1/7066 mAW^-1/5876 mAW^-1 and a noise-equivalent power of 4.04 × 10^–13 WHz^-1/2 / 2.17 × 10^–13 WHz^-1/2 / 2.60 × 10^–13 WHz^-1/2 for UV/Visible/NIR optical signals of weak power density 150 µW/mm² at 0.5 V bias. This study offers a straightforward method for developing a self-powered, broadband photodetector capable of detecting weak optical signals.