Highly responsive photodetectors based on NiPS₃/WS₂ van der Waals type-II heterostructures

A heterostructure photodetector composed of few-layer NiPS₃/WS₂ is made by using mechanical exfoliation and micro-nano fabrication techniques. The photodetector exhibits a broad-band response wavelengths of ranging of 405 nm and 800 nm. Under the light illumination of 405-nm wavelength and a bias voltage of −2 V, the photoresponsivity is 62.6 mA/W and the specific detectivity is 8.59 × 10¹⁰ Jones. In addition, the device demonstrates a relatively fast response with rise and fall times of 70 ms and 120 ms. Theoretical calculation suggest that this excellent performance can be ascribed to the type-II band alignment at the NiPS₃/WS₂ heterostructure interface.