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Microwave Near-Field Imaging of Two-Dimensional Semiconductors

Berweger, Samuel and Weber, Joel C. and John, Jimmy and Velazquez, Jesus M. and Pieterick, Adam and Sanford, Norman A. and Davydov, Albert V. and Brunschwig, Bruce and Lewis, Nathan S. and Wallis, Thomas M. and Kabos, Pavel (2015) Microwave Near-Field Imaging of Two-Dimensional Semiconductors. Nano Letters, 15 (2). pp. 1122-1127. ISSN 1530-6984. doi:10.1021/nl504960u.

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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 MoS_2 and n- and p-doped WSe_2. 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.

Item Type:Article
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URLURL TypeDescription Information
John, Jimmy0000-0002-8772-8939
Brunschwig, Bruce0000-0002-6135-6727
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2015 American Chemical Society. Received: October 24, 2014; Revised: January 20, 2015; Published: January 27, 2015. We would like to thank Will Gannett, Mark Keller, and Alexandra Curtin for helpful advice on sample preparation. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. Mention of commercial products is for informational purposes only, it does not imply NIST’s recommendation or endorsement.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Subject Keywords:Transition metal dichalcogenide; MoS_2; microwave; near-field; quantum capacitance; atomic force microscope
Issue or Number:2
Record Number:CaltechAUTHORS:20150324-085931498
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Official Citation: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, and Pavel Kabos Nano Letters 2015 15 (2), 1122-1127 DOI: 10.1021/nl504960u
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56006
Deposited By: Tony Diaz
Deposited On:24 Mar 2015 16:09
Last Modified:10 Nov 2021 20:53

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