Highly sensitive and broadband photodetectors based on WSe2/MoS2 heterostructures with van der Waals contact electrodes

• Published in: Applied physics letters 2022-07, Vol.121 (2)
• Main Authors: Xiao, Haodong, Lin, Lin, Zhu, Jia, Guo, Junxiong, Ke, Yizhen, Mao, Linna, Gong, Tianxun, Cheng, Huanyu, Huang, Wen, Zhang, Xiaosheng
• Format: Article
• Language: English
• Subjects: Applied physics; Broadband; Electrodes; Electrons; Graphene; Graphical user interface; Heterostructures; Indium tin oxides; Molybdenum disulfide; Photometers; Transition metal compounds; Wireless communications
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0100191

A nanoscale photodetector is a crucial part of intelligent imaging and wireless communication devices. Building van der Waals (vdWs) heterostructures based on two-dimensional transition metal dichalcogenides is thought to be a smart approach for achieving nanoscale photodetectors. However, the pinning effect induced by surface states, defects, and metal-induced gap states during the fabrication process of vdWs heterostructures and contacting electrodes leads to a large Schottky barrier and consequently limits the photoresponse of vdWs heterostructures. In this study, a photodetector based on the WSe2/MoS2 heterostructure with graphene (Gr)/indium tin oxide (ITO) hybrid electrodes has been fabricated. The vdWs contacts established between the exfoliated graphene layers and WSe2/MoS2 heterostructure are able to get rid of lattice damages caused by atom bombardment during the deposition of metal electrodes. In addition, the reduced Schottky barrier at graphene/heterostructure interfaces facilitates the transport of carriers. Experimental results show that the photodetector based on WSe2/MoS2 heterostructures with Gr/ITO hybrid electrodes exhibits a high responsivity of up to 1236.5 A W−1, a detectivity of up to 1.23 × 1013 Jones, and a fast response of 270/130 μs to light from the ultraviolet to near-infrared range.