2D In2S3 Nanoflake Coupled with Graphene toward High‐Sensitivity and Fast‐Response Bulk‐Silicon Schottky Photodetector

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2019-11, Vol.15 (47), p.n/a
• Main Authors: Lu, Jianting, Zheng, Zhaoqiang, Yao, Jiandong, Gao, Wei, Zhao, Yu, Xiao, Ye, Li, Jingbo
• Format: Article
• Language: English
• Subjects: 2D In2S3; Dark current; Electromagnetic absorption; Electronic devices; fast response; Graphene; graphene/Si; Heterojunctions; high sensitivity; Nanotechnology; Optoelectronics; Order parameters; Performance degradation; photodetectors; Photometers; Photovoltaic effect; Sensitivity; Silicon; Two dimensional materials
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201904912

Silicon‐based electronic devices, especially graphene/Si photodetectors (Gr/Si PDs), have triggered tremendous attention due to their simple structure and flexible integration of the Schottky junction. However, due to the relatively poor light–matter interaction and mobility of silicon, these Gr/Si PDs typically suffer an inevitable compromise between photoresponsivity and response speed. Herein, a novel strategy for coupling 2D In2S3 with Gr/Si PDs is demonstrated. The introduction of the double‐heterojunction design not only strengthens the light absorption of graphene/Si but also combines the advantages of the photogating effect and photovoltaic effect, which suppresses the dark current, accelerates the separation of photogenerated carriers, and brings photoconductive gain. As a result, In2S3/graphene/Si devices present an ultrahigh photoresponsivity of 4.53 × 104 A W−1 and fast response speed less than 40 µs, simultaneously. These parameters are an order of magnitude higher than pristine Gr/Si PDs and among the best values compared with reported 2D materials/Si heterojunction PDs. Furthermore, the In2S3/graphene/Si PD expresses outstanding long‐term stability, with negligible performance degradation even after 1 month in air or 1000 cycles of operation. These findings highlight a simple and novel strategy for constructing high‐sensitivity and ultrafast Gr/Si PDs for further optoelectronic applications. A novel strategy for coupling 2D In2S3 with graphene/Si photodetectors is demonstrated. The introduction of a double‐heterojunction design not only strengthens the light absorption of graphene/Si but also combines the advantages of the photogating effect and photovoltaic effect, which suppresses the dark current, accelerates the separation of photogenerated carriers, and brings photoconductive gain.