Graphene/Organic Semiconductor Heterojunction Phototransistors with Broadband and Bi‐directional Photoresponse

• DOI: 10.1002/adma.201804020
• Publication Date: 2018-10-02T06:09:50Z
• Authors: Jiayue Han; Jun Wang; Ming Yang; Xiao Kong; Xiaoqing Chen; Zehua Huang; Hui Guo; Jun Gou; Silu Tao; Zhijun Liu; Zhiming Wu; Yadong Jiang; Xinran Wang
• Keywords: Organic semiconductor

A graphene-semiconductor heterojunction is very attractive for realizing highly sensitive phototransistors due to the strong absorption of semiconductor layer and fast charge transport in graphene. However, photoresponse usually limited a narrow spectral range determined by bandgap semiconductor. Here, an organic (C60 /pentacene) incorporated on graphene realize broadband (405-1550 nm) phototransistor with high gain 5.2 × 105 response time down 275 µs. The visible near-infrared parts photoresponsivity (9127 W-1 @650 nm 1800 @808 come from graphene, respectively. For first time, bi-directional (positive negative) demonstrated at different wavelengths, opposite transfer direction photoexcited carriers enforced unique band alignment. Such tunability will enable new functionalities such as large-scale real-time optical image infrared focal plane array detection future.