Microwave Near-Field Imaging of Two-Dimensional Semiconductors

Samuel Berweger, Joel C. Weber, Jimmy John, Jesus M. Velazquez, Adam Pieterick, Norman A. Sanford, Albert V. Davydov, Bruce Brunschwig, Nathan S. Lewis, Thomas M. Wallis, Pavel Kabos

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Optimizing new generations of two-dimensional devices based on van der Waals materials will require techniques capable of measuring variations in electronic properties in situ and with nanometer spatial resolution. We perform scanning microwave microscopy (SMM) imaging of single layers of MoS2 and n- and p-doped WSe2. By controlling the sample charge carrier concentration through the applied tip bias, we are able to reversibly control and optimize the SMM contrast to image variations in electronic structure and the localized effects of surface contaminants. By further performing tip bias-dependent point spectroscopy together with finite element simulations, we distinguish the effects of the quantum capacitance and determine the local dominant charge carrier species and dopant concentration. These results underscore the capability of SMM for the study of 2D materials to image, identify, and study electronic defects.

Original languageEnglish
Pages (from-to)1122-1127
Number of pages6
JournalNano letters
Issue number2
Publication statusPublished - Feb 11 2015


  • MoS
  • Transition metal dichalcogenide
  • atomic force microscope
  • microwave
  • near-field
  • quantum capacitance

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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