title: Negative Electro-conductance in Suspended 2D WS2Nanoscale Devices.
abstract: We study the in situ electro-conductance in nanoscale electronic devices composed of suspended monolayer WS2with metal electrodes inside an aberration-corrected transmission electron microscope. Monitoring the conductance changes when the device is exposed to the electron beam of 80 keV energy reveals a reversible decrease in conductivity with increasing beam current density. The response time of the electro-conductance when exposed to the electron beam is substantially faster than the recovery time when the beam is turned off. We propose a charge trap model that accounts for excitation of electrons into the conduction band and localized trap states from energy supplied by inelastic scattering of incident 80 keV electrons. These results show how monolayer transition metal dichalcogenide 2D semiconductors can be used as transparent direct electron detectors in ultrathin nanoscale devices.
authors.affiliation: Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
authors.forename: Ye
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
authors.forename: Alex W
authors.initials: AW
authors.lastname: Robertson
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Tweedie
authors.affiliation: Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
authors.forename: Yingqiu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: IFW Dresden , P.O. Box D-01171 Dresden, Germany.|College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China.|Centre of Polymer and Carbon Materials, Polish Academy of Sciences , M. Curie-Sklodowskiej 34, Zabrze 41-819, Poland.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rummeli
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Haimei
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
authors.forename: Jamie H
authors.initials: JH
authors.lastname: Warner
keywords: 2D; TEM; WS2; electro-conductance; in situ