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 (MoS2)/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.