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Search Publications by: Samuel Berweger (Fed)

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Displaying 26 - 31 of 31

Near-field microwave microscopy of one-dimensional nanostructures

May 23, 2016
Author(s)
Samuel Berweger, Paul T. Blanchard, Rebecca C. Quardokus, Frank W. DelRio, Thomas Mitchell (Mitch) Wallis, Pavel Kabos, Sergiy Krylyuk, Albert Davydov
With the ability to measure sample conductivity with nanometer spatial resolution, scanning microwave microscopy (SMM) is a powerful tool to study nanoscale electronic systems and devices. Here we demonstrate the general capability to image electronic

Near-field control and imaging of free charge carrier variations in GaN nanowires

February 15, 2016
Author(s)
Samuel Berweger, Paul T. Blanchard, Matthew Brubaker, Kevin J. Coakley, Norman A. Sanford, Thomas Mitchell (Mitch) Wallis, Kris A. Bertness, Pavel Kabos
Despite their uniform crystallinity, the shape and faceting of semiconducting nanowires (NWs) can give rise to variations in structure and associated electronic properties. Here we investigate local variations in electronic structure across individual n

Amplitude and phase-resolved nano-spectral imaging of surface phonon polaritons in hexagonal boron nitride

June 9, 2015
Author(s)
Samuel Berweger, Shi Zhiwen, Hans A. Bechtel, Sun Yinghui, Zeng Bo, Jin Chenhao, Chang Henry, Michael C. Martin, Markus B. Raschke, Feng Wang
Phonon polaritons are quasiparticles resulting from strong coupling of photons with optical phonons. Excitation and control of these quasiparticles in 2D materials offer the opportunity to confine and transport light at the nanoscale. Here, we image the

Microwave Near-Field Imaging of Two-Dimensional Semiconductors

January 27, 2015
Author(s)
Samuel Berweger, Joel Weber, Jimmy J. Li, Jesus M. Velazquez, Adam Pieterick, Norman A. Sanford, Albert V. Davydov, Thomas Mitchell (Mitch) Wallis, Pavel Kabos
Optimizing new generations of 2D 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

GaN nanowire coated with atomic layer deposition of tungsten: a probe for near-field scanning microwave microscopy

September 25, 2014
Author(s)
Joel Weber, Paul T. Blanchard, Aric Sanders, Jonas Gertsch, Steven George, Samuel Berweger, Atif A. Imtiaz, Thomas Mitchell (Mitch) Wallis, Kris A. Bertness, Pavel Kabos, Norman A. Sanford, victor bright
We report on the fabrication of a GaN nanowire probe for near-field scanning microwave microscopy. The probe has a capacitive resolution of 0.03 fF, surpassing that of a commercial Pt tip. Imaging of MoS2 sheets found the probe to be immune to surface