Monolayer Graphene/Germanium Schottky Junction As High-Performance Self-Driven Infrared Light Photodetector

• Published in: ACS applied materials & interfaces Vol. 5; no. 19; pp. 9362 - 9366
• Main Authors: Zeng, Long-Hui, Wang, Ming-Zheng, Hu, Han, Nie, Biao, Yu, Yong-Qiang, Wu, Chun-Yan, Wang, Li, Hu, Ji-Gang, Xie, Chao, Liang, Feng-Xia, Luo, Lin-Bao
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 09.10.2013
• Subjects: detection limit; Equipment Design; germanium; Germanium - chemistry; graphene; Graphite - chemistry; infrared radiation; Infrared Rays; Light; Semiconductors; Silicon - chemistry; Schottky junction; response speed; infrared photodetector; heterojunction; photovoltaic effect
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/am4026505

We report on the simple fabrication of monolayer graphene (MLG)/germanium (Ge) heterojunction for infrared (IR) light sensing. It is found that the as-fabricated Schottky junction detector exhibits obvious photovoltaic characteristics, and is sensitive to IR light with high I light/I dark ratio of 2 × 104 at zero bias voltage. The responsivity and detectivity are as high as 51.8 mA W–1 and 1.38 × 1010 cm Hz1/2 W–1, respectively. Further photoresponse study reveals that the photovoltaic IR detector displays excellent spectral selectivity with peak sensitivity at 1400 nm, and a fast light response speed of microsecond rise/fall time with good reproducibility and long-term stability. The generality of the above results suggests that the present MLG/Ge IR photodetector would have great potential for future optoelectronic device applications.