Deep multiband photodetectors enabled by reconfigurable band alignment in van der Waals heterostructures

Multiband recognition technology is being extensively investigated because of the increasing demand for on-chip, multifunctional, and sensitive devices that can distinguish coincident spectral information. Most existing multiband imagers use large arrays of photodetectors to capture different spectral components, from which their spectrum is reconstructed. A single device embedded with a convolutional neural network (CNN) capable of recognizing multiband photons allows the footprints of multiband recognition chips to be scaled down while achieving spectral resolution approaching that of benchtop systems. Here, we report a multiple and broadband photodetector based on 2D/3D van der Waals p/n/p heterostructures [p-germanium (Ge)/n-molybdenum disulfide (MoS 2 )/p-black phosphorus (bP)] with an electrically tunable transport-mediated spectral photoresponse. The devices show bias-tunable multiband photodetection (visible, short-wave infrared, and mid-wave infrared photoresponse). Further combination with the CNN algorithm enables crosstalk suppression of photoresponse to different wavelengths and high-accuracy blackbody radiation temperature recognition. The deep multiband photodetection strategies demonstrated in this work may open pathways towards the integration of multiband vision for application in on-chip neural network perception.