Controlling the dynamic processes,
such as generation, separation,
transport, and recombination, of photoexcited carriers in a semiconductor
is foundational in the design of various devices for optoelectronic
applications. One may imagine that if different processes can be manipulated
in one single device and thus generate useful signals, a multifunctional
device can be realized, and the toolbox for integrated optoelectronics
will be expanded. Here, we revealed that in a graphene/ZnTe/graphene
van der Waals (vdW) heterostructure, the carriers can be generated
by illumination from visible to infrared frequencies, and thus, the
detected spectrum range extends to the communication band, well beyond
the band gap of ZnTe (2.26 eV). More importantly, we are able to control
the competition between separation and recombination of the photoexcited
carriers by an electric bias along the thickness-defined channel of
the ZnTe flake: as the bias increases, the photodetecting performance,
e.g. response speed and photocurrent, are improved due to the efficient
separation of carriers; synchronously, the photoluminescence (PL)
intensity decreases and even switches off due to the suppressed recombination
process. The ZnTe-based vdW heterostructure device thus integrates
both photodetection and PL switching functions by manipulating the
generation, separation, transport, and recombination of carriers,
which may inspire the design of the next generation of miniaturized
optoelectronic devices based on the vdW heterostructures made by various
thin flakes.