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Search Publications by: Norman A. Sanford (Fed)

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Displaying 1 - 25 of 319

Atom Probe Tomography Using an Extreme Ultraviolet Trigger Pulse

September 1, 2023
Author(s)
Benjamin Caplins, Ann Chiaramonti Debay, Jacob Garcia, Norman A. Sanford, Luis Miaja Avila
Atom probe tomography (APT) is a powerful materials characterization technique capable of measuring the isotopically resolved three-dimensional (3D) structure of nanoscale specimens with atomic resolution. Modern APT instrumentation most often uses an

Fabrication of Specimens for Atom Probe Tomography using a Combined Gallium and Neon Focused Ion Beam Milling Approach

August 16, 2023
Author(s)
Frances Allen, Paul Blanchard, David Pappas, Russell Lake, Deying Xia, John Notte, Ruopeng Zhang, Andrew Minor, Norman A. Sanford
We demonstrate a new focused ion beam sample preparation method for atom probe tomography. The key aspect of the new method is that we use a neon ion beam for the final tip shaping after conventional annulus milling using gallium ions. This dual-ion

Laser-assisted atom probe tomography of c-plane and m-plane InGaN test structures

April 29, 2022
Author(s)
Norman A. Sanford, Paul T. Blanchard, Alexana Roshko, Ashwin Rishinaramangalam, Daniel Feezell, Albert Davydov
Laser-assisted atom probe tomography (L-APT) was used to measure the indium mole fraction x of c-plane, MOCVD-grown, GaN/InxGa1-xN/GaN test structures and the results were compared with Rutherford backscattering analysis (RBS). Four separate sample types

Bulk-Like Properties Observed From High Density GaN Nanocolumns Grown by Molecular Beam Epitaxy

October 12, 2021
Author(s)
J E. Van Nostrand, R Cortez, J Boecki, J D. Albrecht, C E. Stutz, K L. Averett, Norman Sanford, Albert Davydov
Vertical GaN nanocolumns (NCs) having a width of 90+10 nm and a length of the film thickness were grown by plasma-assisted molecular beam epitaxy on Al_subscript 2)O_subscript 3} (0001). Low temperature photo-luminescence measurements of NC films results

Comparative Apex Electrostatics of Atom Probe Tomography Specimens

April 28, 2021
Author(s)
Qihua Zhang, B. Klein, Norman A. Sanford, Ann Chiaramonti Debay
Laser-assisted atom probe tomography (APT) is the only known analytical method that can simultaneously provide sub-nm 3D spatial resolution and quantitative sensitivity approaching 1 ppm. APT has been applied with great success to the analysis of metals

Crystallographic Polarity Measurements in Two-Terminal GaN Nanowire Devices by Lateral Piezoresponse Force Microscopy

July 23, 2020
Author(s)
Matthew Brubaker, Alexana Roshko, Samuel Berweger, Paul T. Blanchard, Todd E. Harvey, Norman A. Sanford, Kris A. Bertness
Lateral piezoresponse force microscopy (L-PFM) is demonstrated as a reliable method for determining the crystallographic polarity of individual, dispersed GaN nanowires that were functional components in electrical test structures. In contrast to PFM

An Algorithm for Correcting Systematic Energy Deficits in the Atom Probe Mass Spectra of Insulating Samples

April 15, 2020
Author(s)
Benjamin W. Caplins, Paul T. Blanchard, Ann C. Chiaramonti Debay, David R. Diercks, Luis Miaja Avila, Norman A. Sanford
Improvements in the mass resolution of a mass spectrometer directly correlate to improvements in peak identification and quantification. Here we describe a post-processing technique developed to increase the quality of mass spectra of strongly insulating

Atom Probe Tomography using Extreme-Ultraviolet Light

March 27, 2020
Author(s)
Luis Miaja Avila, Ann C. Chiaramonti Debay, Benjamin W. Caplins, David R. Diercks, Brian Gorman, Norman A. Sanford
We present a different approach to laser-assisted atom probe tomography, where instead of using a near-UV laser for inducing a thermal transient, we use an extreme-ultraviolet coherent light source to trigger eld ion emission at the tip's apex. The use of