title: Broadband photodetectors based on graphene-Bi2Te3 heterostructure.
abstract: Recently, research on graphene based photodetectors has drawn substantial attention due to ultrafast and broadband photoresponse of graphene. However, they usually have low responsivity and low photoconductive gain induced by the gapless nature of graphene, which greatly limit their applications. The synergetic integration of graphene with other two-dimensional (2D) materials to form van der Waals heterostructure is a very promising approach to overcome these shortcomings. Here we report the growth of graphene-Bi2Te3 heterostructure where Bi2Te3 is a small bandgap material from topological insulator family with a similar hexagonal symmetry to graphene. Because of the effective photocarrier generation and transfer at the interface between graphene and Bi2Te3, the device photocurrent can be effectively enhanced without sacrificing the detecting spectral width. Our results show that the graphene-Bi2Te3 photodetector has much higher photoresponsivity (35 AW(-1) at a wavelength of 532 nm) and higher sensitivity (photoconductive gain up to 83), as compared to the pure monolayer graphene-based devices. More interestingly, the detection wavelength range of our device is further expanded to near-infrared (980 nm) and telecommunication band (1550 nm), which is not observed on the devices based on heterostructures of graphene and transition metal dichalcogenides.
authors.affiliation: Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215123, P. R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Qiao
authors.forename: Jian
authors.initials: J
authors.lastname: Yuan
authors.forename: Zaiquan
authors.initials: Z
authors.lastname: Xu
authors.forename: Caiyun
authors.initials: C
authors.lastname: Chen
authors.forename: Shenghuang
authors.initials: S
authors.lastname: Lin
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Jingchao
authors.initials: J
authors.lastname: Song
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Qasim
authors.initials: Q
authors.lastname: Khan
authors.forename: Hui Ying
authors.initials: HY
authors.lastname: Hoh
authors.forename: Chun-Xu
authors.initials: CX
authors.lastname: Pan
authors.forename: Shaojuan
authors.initials: S
authors.lastname: Li
authors.forename: Qiaoliang
authors.initials: Q
authors.lastname: Bao
keywords: broadband; graphene; heterostructure; photodetector; photoresponsivity; sensitivity