title: Synergistic Effects of Plasmonics and Electron Trapping in Graphene Short-Wave Infrared Photodetectors with Ultrahigh Responsivity.
abstract: Graphene's unique electronic and optical properties have made it an attractive material for developing ultrafast short-wave infrared (SWIR) photodetectors. However, the performance of graphene SWIR photodetectors has been limited by the low optical absorption of graphene as well as the ultrashort lifetime of photoinduced carriers. Here, we present two mechanisms to overcome these two shortages and demonstrate a graphene-based SWIR photodetector with high responsivity and fast photoresponse. In particular, a vertical built-in field is employed in the graphene channel for trapping the photoinduced electrons and leaving holes in graphene, which results in prolonged photoinduced carrier lifetime. On the other hand, plasmonic effects were employed to realize photon trapping and enhance the light absorption of graphene. Thanks to the above two mechanisms, the responsivity of this proposed SWIR photodetector is up to a record of 83 A/W at a wavelength of 1.55 μm with a fast rising time of less than 600 ns. This device design concept addresses key challenges for high-performance graphene SWIR photodetectors and is promising for the development of mid/far-infrared optoelectronic applications.
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Zefeng
authors.identifier: 0000-0002-0689-8443
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Xinming
authors.identifier: 0000-0002-7844-8417
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Li
authors.identifier: 0000-0002-7757-1149
authors.initials: L
authors.lastname: Tao
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Long
authors.affiliation: SUTD-MIT International Design Centre (IDC), Engineering Product Development, Singapore University of Technology and Design , 8 Somapah Road, Singapore 487372.
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Liang
authors.affiliation: SUTD-MIT International Design Centre (IDC), Engineering Product Development, Singapore University of Technology and Design , 8 Somapah Road, Singapore 487372.
authors.forename: Lay Kee
authors.identifier: 0000-0003-2811-1194
authors.initials: LK
authors.lastname: Ang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Chester
authors.initials: C
authors.lastname: Shu
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Hon Ki
authors.initials: HK
authors.lastname: Tsang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong , Hong Kong SAR, China.
authors.forename: Jian-Bin
authors.initials: JB
authors.lastname: Xu
keywords: fast photoresponse; graphene; plasmonics; short-wave infrared photodetector; ultrahigh responsivity