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Search Publications by: Norman A. Sanford (Fed)

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Displaying 26 - 50 of 319

Field Ion Emission in an Atom Probe Microscope Triggered by Femtosecond-Pulsed Coherent Extreme Ultraviolet Light

March 12, 2020
Author(s)
Ann C. Chiaramonti Debay, Luis Miaja Avila, Benjamin W. Caplins, Paul T. Blanchard, Norman A. Sanford, Brian Gorman, David R. Diercks
This paper reports construction of an extreme ultraviolet (EUV) radiation-triggered atom probe tomograph and describes the results from initial experiments on amorphous SiO2. Femtosecond-pulsed coherent EUV radiation of 29.6 nm wavelength (41.85 eV photon

An Atom Probe Tomograph Incorporating a Wavelength-Tuneable Femtosecond-Pulsed Coherent Extreme Ultraviolet Light Source

June 19, 2019
Author(s)
Ann C. Chiaramonti Debay, Luis Miaja Avila, Paul T. Blanchard, David R. Diercks, Brian Gorman, Norman A. Sanford
Pulsed coherent extreme ultraviolet (EUV) radiation is a potential promising alternative to pulsed infra-red, visible, and near- ultraviolet laser sources for atom probe tomography. In addition to having the benefit of high absorption across the periodic

Laser-assisted atom probe tomography of Ti/TiN films deposited on Si

December 21, 2016
Author(s)
Norman A. Sanford, Paul T. Blanchard, Ryan M. White, Michael R. Vissers, Albert Davydov, D R. Diercks, David P. Pappas
Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss

Raman spectroscopy based measurements of carrier concentration in n-type GaN nanowires grown by plasma-assisted molecular beam epitaxy

September 30, 2016
Author(s)
Lawrence H. Robins, Elizabeth Horneber, Norman A. Sanford, Kristine A. Bertness, John B. Schlager
The carrier concentration in ensembles of n-type GaN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy was determined by curve-fitting analysis of Raman spectra, based on modeling of the carrier concentration dependence of the longitudinal

Spontaneous growth of GaN nanowire nuclei on N- and Al-polar AlN: A piezoresponse force microscopy study of crystallographic polarity

March 2, 2016
Author(s)
Matthew D. Brubaker, Alexana Roshko, Paul T. Blanchard, Todd E. Harvey, Norman A. Sanford, Kristine A. Bertness
The polarity of gallium nitride (GaN) nanowire nuclei grown on AlN layers was studied by piezoresponse force microscopy (PFM). N- or Al-polar AlN layers were grown by molecular beam epitaxy (MBE) on Si (111) substrates by use of Al- or N-rich growth

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

Polarity-Controlled GaN/AlN Nucleation Layers for Selective-Area Growth of GaN Nanowire Arrays on Si(111) Substrates by Molecular Beam Epitaxy

December 18, 2015
Author(s)
Matthew D. Brubaker, Shannon M. Duff, Todd E. Harvey, Paul T. Blanchard, Alexana Roshko, Aric W. Sanders, Norman A. Sanford, Kristine A. Bertness
We have demonstrated dramatic improvement in the quality of selective-area GaN nanowire growth by controlling the polarity of the underlying nucleation layers. In particular, we find that N- polarity is beneficial for the growth of large ordered nanowire

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

Measurement of the Electrostatic Edge Effect in Wurtzite GaN Nanowires

November 24, 2014
Author(s)
Alex Henning, Benjamin Klein, Kristine A. Bertness, Paul T. Blanchard, Norman Sanford, Yossi Rosenwaks
The electrostatic effect of the hexagonal corner on the electronic structure in wurtzite GaN nanowires (NWs) was directly measured using Kelvin probe force microscopy (KPFM). By correlating electrostatic simulations with the measured potential difference