The condensation of electrons and holes in 2D photocells of ultrathin MoTe2

ORAL

Abstract

In semiconductors, electrons and holes above a certain critical density may condense into a liquid phase containing a macroscopic population of highly correlated electrons and holes. Strikingly, under optical excitation, ultrathin MoTe2 photocells undergo this transition even at room temperature (295 K). Using a new technique called Multi-Parameter Dynamic Photoresponse Microscopy (MPDPM) we image the photoresponse of two-dimensional graphene-MoTe2-graphene photocells over several dynamical variables, including laser power, pump-probe delay and applied voltage. MPDPM reveals that above a critical threshold a ring-like spatial feature abruptly forms in the photoresponse as a function of increasing optical power. This pattern, combined with time-resolved photocurrent dynamics also revealed by MPDPM, provides strong evidence for the formation of an electron-hole condensate at room temperature.

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Presenters

  • Trevor Arp

    Department of Physics and Astronomy, Univ of California - Riverside

Authors

  • Trevor Arp

    Department of Physics and Astronomy, Univ of California - Riverside

  • Dennis Pleskot

    Department of Materials Science and Engineering, Univ of California - Riverside, Materials Science and Engineering, University of California Riverside, Univ of California - Riverside

  • Vivek Aji

    Physics & Astronomy, Univ of California - Riverside, Department of Physics and Astronomy, Univ of California - Riverside, Univ of California - Riverside, Physics and Astronomy, University of California Riverside

  • Nathaniel Gabor

    Physics, Univ of California - Riverside, Physics & Astronomy, Univ of California - Riverside, Department of Physics and Astronomy, Univ of California - Riverside, Univ of California - Riverside, Physics and Astronomy, University of California Riverside, Physics, University of California Riverside