Tunable Photoresponse in 2D WTe2/MoS2 Van der Waals Heterojunctions

Weyl semimetals haveattracted extensive research interests due to their unique topological properties. However, photoelectric devices based on pristine semimetals with large electrical conductivity are hard to detect especially under weak light. Here, with the help of MoS2, a stable van der Waals semiconductor, WTe2/MoS2 van der Waals heterojunctions are designed to successfully realize stable photoresponse from visible light to near-infrared. Tunable photocurrent is observed compared to pristine MoS2 with faster response under the effect of semimetal WTe2. Our study illustrates the great potential of WTe2 and other topological semimetals in photodetectors.