title: An Atomically Layered InSe Avalanche Photodetector.
abstract: Atomically thin photodetectors based on 2D materials have attracted great interest due to their potential as highly energy-efficient integrated devices. However, photoinduced carrier generation in these media is relatively poor due to low optical absorption, limiting device performance. Current methods for overcoming this problem, such as reducing contact resistances or back gating, tend to increase dark current and suffer slow response times. Here, we realize the avalanche effect in a 2D material-based photodetector and show that avalanche multiplication can greatly enhance the device response of an ultrathin InSe-based photodetector. This is achieved by exploiting the large Schottky barrier formed between InSe and Al electrodes, enabling the application of a large bias voltage. Plasmonic enhancement of the photosensitivity, achieved by patterning arrays of Al nanodisks onto the InSe layer, further improves device efficiency. With an external quantum efficiency approaching 866%, a dark current in the picoamp range, and a fast response time of 87 μs, this atomic layer device exhibits multiple significant advances in overall performance for this class of devices.
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Sidong
authors.initials: S
authors.lastname: Lei
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.|§Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Wen
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Liehui
authors.initials: L
authors.lastname: Ge
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Sina
authors.initials: S
authors.lastname: Najmaei
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Antony
authors.initials: A
authors.lastname: George
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Yongji
authors.initials: Y
authors.lastname: Gong
authors.affiliation: ⊥Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.
authors.forename: Weilu
authors.initials: W
authors.lastname: Gao
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Zehua
authors.initials: Z
authors.lastname: Jin
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Lou
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.|∥Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States.|⊥Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Kono
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Vajtai
authors.affiliation: †Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.|‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Pulickel
authors.initials: P
authors.lastname: Ajayan
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.|§Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States.|∥Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States.|⊥Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Halas
keywords: 2D photodetector; InSe; avalanche effect; impact ionization