GeSe/MoTe₂ vdW heterostructure for UV–VIS–NIR photodetector with fast response

GeSe is a layered p-type semiconductor with intriguing optoelectrical properties such as high absorption coefficient, high carrier mobility, and narrow bandgap, which promises a broadband photoresponse over a wide spectral range. However, GeSe based broadband photodetectors could not achieve both high responsivity and fast response speed. Therefore, it is urgent to improve the properties of GeSe based broadband photodetectors. Herein, a GeSe/MoTe₂ van der Waals (vdW) heterostructure was designed. The GeSe/MoTe₂ vdW heterostructure possesses broadband photodetection over ultraviolet, visible, and near infrared. The device has competitive responsivity (R) and detectivity (D^*) over a broadband even at 1050 nm, which are 28.4 A/W and 5.6 × 10⁹ Jones, respectively. Excitingly, the response speed for 365 nm is as fast as 3 μs, which is much faster than most other GeSe devices. Overall, our results suggest that the GeSe/MoTe₂ heterostructure can provide an effective strategy to achieve broadband photodetectors with both high responsivity and fast response.