Bias-dependent photoresponse of T_d-WTe₂ grown by chemical vapor deposition

Abstract

The type-II Weyl semimetal Td-WTe2 is one of the wonder materials for high-performance optoelectronic devices. We report the self-powered Td-WTe2 photodetectors and their bias-dependent photoresponse in the visible region (405, 520, 638 nm) driven by the bulk photovoltaic effect. The device shows the responsivity of 15.8 mAW−1 and detectivity of 5.2 × 109 Jones at 520 nm. Besides, the response time of the WTe2 photodetector shows the strong bias-voltage dependent property. This work offers a physical reference for understanding the photoresponse process of Td-WTe2 photodetectors.