Conclusion: We have demonstrated a highly efficient visible-NIR photodetector based on the interlayer optical transition. Indirect interlayer transitions can occur proved by DFT calculations. In particular, the exciton current is tuned by an external gate field and the cutoff wavelength is increased to 1500 nm. Remarkably, there is a peak of about 2.75 nA at Vg = 5 V around 1075 nm wavelength. Finally, this study on utilizing interlayer excitons for spatially separated electrons and holes in different layers is expected to offer a novel binary and ternary heterojunction device to overcome the limitation of the intrinsic band for high-performance NIR photodetectors.