Intrinsic Photoconductivity Imaging of Monolayer-Bilayer WSe2 Flakes

ORAL

Abstract

The spatial variation of photo response in few-layer transition metal dichalcogenides (TMDCs) is of critical importance for their applications in optoelectronic devices. In conventional microscopy experiments, the local distribution of photocurrent across source and drain electrodes is measured, which may be complicated by the diffusion of photo-induced carriers, the Schottky contact, and other extrinsic effects. Using a microwave impedance microscope (MIM) with light stimulation, we demonstrate the intrinsic photoconductivity mapping of CVD-grown WSe2 flakes without the need of contact electrodes. The measured photoconductivity as a function of the above-gap laser intensity in the bilayer WSe2 region is around one order of magnitude higher than that in the monolayer area, indicative of a significant enhancement of the carrier lifetime due to interlayer coupling. The noninvasive MIM imaging is expected to provide important insights on the remarkable electrical and optical properties of TMDCs.

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Presenters

  • Zhaodong Chu

    University of Texas at Austin, Department of Physics, University of Texas at Austin

Authors

  • Zhaodong Chu

    University of Texas at Austin, Department of Physics, University of Texas at Austin

  • Ali Han

    King Abdullah University of Science and Technology

  • Chao Lei

    Physics department, University of Texas at Austin, Physics, University of Texas, Austin, University of Texas at Austin, The University of Texas at Austin

  • Di Wu

    University of Texas at Austin, Univ of Texas, Austin, Department of Physics, University of Texas at Austin

  • Xiaoqin (Elaine) Li

    University of Texas at Austin, Department of Physics, Univerisity of Texas at Austin, Department of Physics, Univ of Texas, Austin, Univ of Texas, Austin

  • Lain-Jong Li

    King Abdullah University of Science and Technology, KAUST, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology

  • Keji Lai

    University of Texas at Austin, Univ of Texas, Austin, Department of Physics, University of Texas at Austin