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Title: Defect-mediated transport and electronic irradiation effect in individual domains of CVD-grown monolayer MoS2

We study the electrical transport properties of atomically thin individual crystalline grains of MoS2 with four-probe scanning tunneling microscopy. The monolayer MoS2 domains are synthesized by chemical vapor deposition on SiO2/Si substrate. Temperature dependent measurements on conductance and mobility show that transport is dominated by an electron charge trapping and thermal release process with very low carrier density and mobility. The effects of electronic irradiation are examined by exposing the film to electron beam in the scanning electron microscope in an ultrahigh vacuum environment. The irradiation process is found to significantly affect the mobility and the carrier density of the material, with the conductance showing a peculiar time-dependent relaxation behavior. It is suggested that the presence of defects in active MoS2 layer and dielectric layer create charge trapping sites, and a multiple trapping and thermal release process dictates the transport and mobility characteristics. The electron beam irradiation promotes the formation of defects and impact the electrical properties of MoS2. Finally, our study reveals the important roles of defects and the electron beam irradiation effects in the electronic properties of atomic layers of MoS2.
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences
  2. Rice Univ., Houston, TX (United States). Dept. of Materials Science and NanoEngineering
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics
Additional Journal Information:
Journal Volume: 33; Journal Issue: 2; Journal ID: ISSN 2166-2746
American Vacuum Society/AIP
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE electron beams; monolayers; carrier mobility; electron radiation effects; scanning electron microscopy