文章基本信息

标题：Ultrahigh-Gain Photodetectors Based on Atomically Thin Graphene-MoS2 Heterostructures
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作者：Wenjing Zhang ; Chih-Piao Chuu ; Jing-Kai Huang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：4
期号：1
DOI：10.1038/srep03826
语种：English
出版社：Springer Nature
摘要：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 10⁸. 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.