Black Phosphorous/Indium Selenide Photoconductive Detector for Visible and Near‐Infrared Light with High Sensitivity

2D materials offer tremendous opportunities for designing and investigating multifunctional high‐performance electronic and optoelectronic devices. In this contribution, a photogate vertical structure is devised by vertically stacking layered indium selenide (InSe) on top of layered black phosphorous (BP). The photodetector built with the vertical structure possesses a wide response range from 405 to 1550 nm, and the photodetector exhibits a relatively fast (≈22 ms) response and high responsivity of ≈53.80 A W −1 at λ = 655 nm and 43.11 A W −1 at λ = 1550 nm, respectively. Under visible‐light illumination (λ = 655 nm), the external quantum efficiency of the device can reach 1020%. By taking advantage of gate‐tunable modulation, the forward‐to‐reverse bias current ratio is as high as 10 3 . In addition, the environmental degradation of BP could be effectively suppressed by InSe capping. The high sensitivity, broad spectral response, and enhanced stability of the photodetector show that the photogate structure provides a new opportunity for broad spectral detection or imaging at room temperature by using 2D materials with a vertical structure.