Toward High-Performance Self-Driven Photodetectors via Multistacking Van der Waals Heterostructures
Shuai Guo, Zhuo Chen, D. Weller, Xianshuang Wang, Chunjie Ding, Yingying Wang, Ruibin Liu
Abstract
The unique optoelectronic properties of layered van der Waals (vdW) heterostructures open up exciting opportunities for high-performance photodetectors. Self-driven photodetectors are desirable for reducing power consumption and minimizing the device size. Here, a semiconductor–insulator–semiconductor-type multistacking WSe2/graphene/h-BN/MoS2 vdW heterostructure is demonstrated to realize an enhanced self-powered photodetector with a high on–off current ratio of about 1.2 × 105 and a high photoresponsivity of 3.6 A/W without applying bias, which is the highest photoresponsivity ever reported for self-powered photodetectors. Because of the difference in the Fermi level, a built-in electrical field is formed at the WSe2/graphene junction, where the photoexcited electrons and holes can be efficiently separated and the carriers can easily tunnel through the MoS2/h-BN junction driven by the enhanced potential. Therefore, the enhanced self-powered photodetection is attributable to highly efficient carrier tunneling through large h-BN electron barriers. By comparison, when the stacking sequence is changed to make WSe2/MoS2 p–n heterojunctions lay on graphene/h-BN, the self-powered photocurrent is still generated because of the type-II band alignment, which exhibits lower but still relevant values with a light on/off ratio of ∼8 × 103 and a photoresponsivity of ∼2.39 A/W. The efficient enhancement demonstrates that multistacking heterostructures significantly elevate the performance of self-powered photodetectors, providing a feasible route to develop high-performance self-powered optoelectronic devices and extend their applications in integrated optoelectronic systems.