(a) Schematic diagram of the photodetector with BP-on-WSe₂ photogate structure. (b) The photoconductive gain G and detectivity D* of the photodetector for wavelengths ranging from 400 nm to 1600 nm at 1 mW/cm² incident light power density. V_ds=0.5 V. (c) Top: the photocurrent image of the photodetector under 1550 nm illumination with different light polarizations (red arrows). Bottom left: the optical image of the photodetector with BP-on-WSe₂ photogate structure. (d) The photocurrent as a function of light polarization at 100 mW/cm² incident light power density. V_ds=0.5 V. Panels (a)–(d) are reproduced from Ref. [85] with permission from Elsevier.