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 122.55 mA/W to 510.98 mA/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.