Ultrahigh-gain photodetectors based on atomically thin graphene-MoS2 heterostructures.
Due to its high carrier mobility, broadband absorption, and fast response time, the semi-metallic graphene is attractive for optoelectronics. Another two-dimensional semiconducting material molybdenum disulfide (MoS2) is also known as light- sensitive. Here we show that a large-area and continuous MoS2 monolayer is achievable using a CVD method and graphene is transferable onto MoS2. We demonstrate that a photodetector based on the graphene/MoS2 heterostructure is able to provide a high photogain greater than 10(8). Our experiments show that the electron-hole pairs are produced in the MoS2 layer after light absorption and subsequently separated across the layers. Contradictory to the expectation based on the conventional built-in electric field model for metal-semiconductor contacts, photoelectrons are injected into the graphene layer rather than trapped in MoS2 due to the presence of a perpendicular effective electric field caused by the combination of the built-in electric field, the applied electrostatic field, and charged impurities or adsorbates, resulting in a tuneable photoresponsivity.
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan.
Wenjing
W
Zhang
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan.
Chih-Piao
CP
Chuu
1] Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan [2] Department of Photonics, National Chiao Tung University, HsinChu 300, Taiwan.
Jing-Kai
JK
Huang
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan.
Chang-Hsiao
CH
Chen
Graduate Institute of Photonics and Optoelectronics, and Department of ElectricalEngineering, National Taiwan University, Taipei, Taiwan.
Meng-Lin
ML
Tsai
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan.
Yung-Huang
YH
Chang
Department of Physics, National Taiwan University, Taipei, Taiwan.
Chi-Te
CT
Liang
Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
Yu-Ze
YZ
Chen
Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
Yu-Lun
YL
Chueh
Graduate Institute of Photonics and Optoelectronics, and Department of ElectricalEngineering, National Taiwan University, Taipei, Taiwan.
Jr-Hau
JH
He
1] Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan [2] Department of Physics, National Taiwan University, Taipei, Taiwan [3] School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Mei-Yin
MY
Chou
1] Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 11529, Taiwan [2] Department of Physics, National Tsing Hua University, HsinChu 300, Taiwan [3] Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
Lain-Jong
LJ
Li