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.