標題: Scalable van der Waals Heterojunctions for High-Performance Photodetectors
作者: Yeh, Chao-Hui
Liang, Zheng-Yong
Lin, Yung-Chang
Wu, Tien-Lin
Fan, Ta
Chu, Yu-Chen
Ma, Chun-Hao
Liu, Yu-Chen
Chu, Ying-Hao
Suenaga, Kazutomo
Chiu, Po-Wen
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: WS2;graphene;two-dimensional materials;heterostructure;photoresponsivity
公開日期: 18-十月-2017
摘要: Atomically thin two-dimensional (2D) materials have attracted increasing attention for optoelectronic applications in view of their compact, ultrathin, flexible, and superior photosensing characteristics. Yet, scalable growth of 2D heterostructures and the fabrication of integrable optoelectronic devices remain unaddressed. Here, we show a scalable formation of 2D stacks and the fabrication of phototransistor arrays, with each photosensing element made of a graphene-WS2 vertical heterojunction and individually addressable by a local top gate. The constituent layers in the heterojunction are grown using chemical vapor deposition in combination with sulfurization, providing a clean junction interface and processing scalability. The aluminum top gate possesses a self-limiting oxide around the gate structure, allowing for a self-aligned deposition of drain/source contacts to reduce the access (litigated) channel regions and to boost the device performance. The generated photo current, inherently restricted by the limited optical absorption cross section of 2D materials, can be enhanced by 2 orders of magnitude by top gating. The resulting photoresponsivity can reach 4.0 A/W under an illumination power density of 0.5 mW/cm(2), and the dark current can be minimized to few picoamperes, yielding a low noise-equivalent power of 2.5 x 10(-16) W/Hz(1/2). Tailoring 2D heterostacks as well as the device architecture moves the applications of 2D-based optoelectronic devices one big step forward.
URI: http://dx.doi.org/10.1021/acsami.7b10892
http://hdl.handle.net/11536/143966
ISSN: 1944-8244
DOI: 10.1021/acsami.7b10892
期刊: ACS APPLIED MATERIALS & INTERFACES
Volume: 9
起始頁: 36181
結束頁: 36188
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