  Van der Waals (vdWs) heterostructures assembled by stacking 2D crystal layers
have proven to be a new material platform for high-performance optoelectronic
applications such as thin film transistors, photodetectors, and emitters. Here,
we demonstrate a novel device with strain tuning capabilities using MoS2/Sb2Te3
vdWs p-n heterojunction devices designed for photodetection in the visible to
near-infrared spectrum. The heterojunction devices exhibit remarkable
characteristics, such as a low dark current in the range of a few picoamperes
and a high photoresponsivity of 0.12 A/W. Furthermore, the proposed devices
exhibit exceptional tunability when subjected to a compressive strain of up to
0.3%. By introducing strain at the interface of the heterojunction, the
materials bandgap is affected resulting in a significant change in the band
structure of the heterojunction. This leads to a change in the detectors
optical absorption characteristics improving the responsivity of the device.
The proposed strain-induced engineering of the electronic and optical
properties of the stacked 2D crystal materials allows tuning of the
optoelectronic performance of vdWs devices for high-performance and low-power
consumption applications for applications like wearable sensors and flexible
electro-optic circuits.
