High‐Sensitive and Fast Speed UV Photodetector Based on HfSe₂/InSe Heterostructure

Abstract The type‐II band‐aligned van der Waals (vdW) heterostructures are favorable for photocarrier separation and are often used for designing high‐performance photodetectors. Inspired by this, a metal‐mirror electrode enhanced HfSe 2 ‐InSe vdW heterostructure photodetector is designed and demonstrated excitement performance in UV light detection. It is demonstrated the moderate bandgap heterostructure can be configured as a high‐performance UV photodetector with excellent light on/off ratio of 10 6 , high photoresponsivity of 47.3 AW −1 , competitive high specific detectivity of 3.2 × 10 12 cmHz 1/2 W −1 and very low noise equivalent power of 2.8 × 10 −16 WHz −1/2 . Notably, the photoresponse speed of the device is very fast, with a rise time of 4.1 µs and a decay time of 5.4 µs. The results indicate that 2D HfSe 2 ‐InSe vdW heterostructure possesses great potential applications in UV photodetection.