Gate-tunable the interface properties of GaAs-WSe2 (1D-2D) vdWs heterojunction for high-responsivity, self-powered photodetector

Integrated mixed-dimensional (MD) van der Waals (vdWs) heterojunctions for self-powered photodetectors have attracted intense attention. Performances of these photodetectors are highly dependent on the interface properties, including the semiconductor-metal interface and the semiconductor-semiconductor interface. To date, how to balance the interface properties remains to be explored. Here, we explore a straightforward strategy to balance the interface properties of the MD-vdWs heterojunction photodetector, by tuning the Fermi level of ambipolar two-dimensional material with a gate bias. The effectiveness of gate-tunable interface properties is verified by a GaAs-WSe2 MD vdWs heterojunction self-powered photodetector with different metal contacts. Under the gate biasing, the responsivity is enhanced from 122.55mA/W to 510.98mA/W in the GaAs-WSe2 heterojunction photodetector with the Au/Cr electrodes, which is better than the state-of-the-art GaAs-based self-powered photodetectors. This work provides a simple and effective method to fabricate high-responsivity, self-powered heterojunction photodetectors by gate-tunable interface properties.