Photocurrent response in few-layered ReS₂ devices with short and open circuits

We perform photocurrent measurements in few-layered ReS₂ with multiple electrodes using scanning photocurrent microscopy and investigate the photocurrent mechanism of the ReS₂ device. In particular, we have investigated how the photocurrent responds to the different configurations of a current-collecting electrode, ground electrodes and floating electrodes. When all electrodes are electrically connected, the circuit is short. If any electrodes are floating, we refer the circuit is open. Remarkably, open-circuit devices show a similar photocurrent response with short-circuit devices. The observed photocurrent is attributed to the electron response to the modulating electric field that is generated by time-varying laser heating. We further show that the observed photocurrent is tunable by gate voltages.