Ultrahigh-Gain Photodetectors Based on Atomically Thin Graphene-MoS2 Heterostructures

Wenjing Zhang, Chih Piao Chuu, Jing Kai Huang, Chang Hsiao Chen, Meng Lin Tsai, Yung Huang Chang, Chi Te Liang, Yu Ze Chen, Yu Lun Chueh, Jr Hau He, Mei Yin Chou, Lain Jong Li

Research output: Contribution to journalArticlepeer-review

645 Citations (Scopus)

Abstract

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 (MoS 2) is also known as light- sensitive. Here we show that a large-area and continuous MoS 2 monolayer is achievable using a CVD method and graphene is transferable onto MoS 2. We demonstrate that a photodetector based on the graphene/MoS 2 heterostructure is able to provide a high photogain greater than 10 8. Our experiments show that the electron-hole pairs are produced in the MoS 2 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 MoS 2 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.

Original languageEnglish
Article number3826
JournalScientific reports
Volume4
DOIs
Publication statusPublished - 2015 Apr 1

All Science Journal Classification (ASJC) codes

  • General

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