Journal
IEEE TRANSACTIONS ON ELECTRON DEVICES
Volume 68, Issue 4, Pages 1702-1709Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TED.2021.3058087
Keywords
Graphene; Tunneling; Photodetectors; Electrodes; Heterojunctions; Substrates; Performance evaluation; Graphene; heterojunction; photodetector; tunneling
Funding
- National Natural Science Foundation of China (NSFC) [61922005, U1930105]
- Beijing Municipal Natural Science Foundation (BNSF) [JQ20027]
- General Program of Science and Technology Development Project of Beijing Municipal Education Commission [KM202010005005]
- Equipment Pre-Research Project of China Electronics Technology Group Corporation (CETC) [6141B08110104]
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This study presents a vertically stacked tunneling photodetector based on WSe2/graphene/WS2 van der Waals heterostructure. By introducing graphene film into the WSe2/WS2 interface, the interface composition was improved and Fowler-Nordheim tunneling was enhanced. The device shows high responsivity, detectivity, and photocurrent/dark current ratio, outperforming devices without graphene.
The vertical van der Waals heterostructures based on 2-D materials have attracted tremendous attention in optoelectronic devices as they can offer perfect interface without dangling bonds, atomic layer thicknesses, and conveniently tunable energy band alignment. However, the carrier transport mechanism in vertically stacked van der Waals heterostructure photodetectors is usually neglected in regards of photoresponse enhancement strategy, leading to low photoresponsivity and quantum efficiency. Here, we report a vertically stacked tunneling photodetector based on WSe2/graphene/WS2 van der Waals heterostructure. By introducing graphene film into the WSe2/WS2 interface, the interface composition was ameliorated and the Fowler-Nordheim tunneling (FNT) was enhanced with the reduced tunneling barrier height and thickness, caused by the elevated energy level of electrons since strong electron-electron interaction, ultrafast thermalization (similar to 50 fs), and massless Dirac electrons of graphene. Therefore, the device exhibits a high photocurrent/dark current ratio (>10(4)), fast response time (similar to 300 mu s), high detectivity (similar to 1.58 x 10(12) Jones), and high responsivity (429 mA W-1) across a broad spectral range till 1 mu m at room temperature. The optimized detectivity and responsivity are about 150 times and 50 times higher than WSe2/WS2 device without graphene, respectively. These results contribute to offer a novel and versatile strategy for overcoming the performance limitation in van der Waals photodetector.
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