High‐Performance Ultraviolet Photodetector Based on the Vertical GaSe/GaN Heterojunction

Ultraviolet light detection is essential for environmental monitoring, hazard alerting, and optical communication. Here, a vertical UV photodetector is proposed and demonstrated by stacking the freestanding GaN-film on the 2D GaSe flake. Benefits from the vertical heterostructure and built-in electric field, the photodetector exhibits excellent photoresponse properties, including a high responsivity of 1.38 × 10⁵ A/W and a high specific detectivity of 1.40 × 10¹⁶ Jones under 362 nm wavelength illumination. Additionally, the device demonstrates fast rise and decay time of 18.0 and 21.8 µs, respectively. This work paves the way for design and realization of the high-performance GaN-based photodetectors.