title: Highly responsive MoS2 photodetectors enhanced by graphene quantum dots.
abstract: Molybdenum disulphide (MoS2), which is a typical semiconductor from the family of layered transition metal dichalcogenides (TMDs), is an attractive material for optoelectronic and photodetection applications because of its tunable bandgap and high quantum luminescence efficiency. Although a high photoresponsivity of 880-2000 AW(-1) and photogain up to 5000 have been demonstrated in MoS2-based photodetectors, the light absorption and gain mechanisms are two fundamental issues preventing these materials from further improvement. In addition, it is still debated whether monolayer or multilayer MoS2 could deliver better performance. Here, we demonstrate a photoresponsivity of approximately 10(4) AW(-1) and a photogain of approximately 10(7) electrons per photon in an n-n heterostructure photodetector that consists of a multilayer MoS2 thin film covered with a thin layer of graphene quantum dots (GQDs). The enhanced light-matter interaction results from effective charge transfer and the re-absorption of photons, leading to enhanced light absorption and the creation of electron-hole pairs. It is feasible to scale up the device and obtain a fast response, thus making it one step closer to practical applications.
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: Caiyun
authors.initials: C
authors.lastname: Chen
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.affiliation: 1] 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 [2] Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China.
authors.forename: Shenghuang
authors.initials: S
authors.lastname: Lin
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China.
authors.forename: Chi
authors.initials: C
authors.lastname: Man Luk
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: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Materials Engineering, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Zaiquan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Materials Engineering, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Jingchao
authors.initials: J
authors.lastname: Song
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: Yunzhou
authors.initials: Y
authors.lastname: Xue
authors.affiliation: School of Physical and Technology, Wuhan University, Wuhan 430072, P. R. China.
authors.forename: Delong
authors.initials: D
authors.lastname: Li
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: Jian
authors.initials: J
authors.lastname: Yuan
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: Wenzhi
authors.initials: W
authors.lastname: Yu
authors.affiliation: School of Physical and Technology, Wuhan University, Wuhan 430072, P. R. China.
authors.forename: Chunxu
authors.initials: C
authors.lastname: Pan
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Ping Lau
authors.affiliation: 1] 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 [2] Department of Materials Engineering, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Qiaoliang
authors.initials: Q
authors.lastname: Bao