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Search Publications by: Angela R. Hight Walker (Fed)

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Displaying 1 - 25 of 178

Reproducible graphene synthesis by oxygen-free chemical vapour deposition

May 29, 2024
Author(s)
Jacob Amontree, Xingzhou Yan, Christopher DiMarco, Pierre Levesque, Tehseen Adel, Jordan Pack, Madisen Holbrook, Christian Cupo, Zhiying Wang, Dihao Sun, Adam Biacchi, Charlezetta Stokes, Kenji Watanabe, Takashi Taniguchi, Cory Dean, Angela R. Hight Walker, Katayun Barmak, Richard Martel, James Hone
The demonstration of large-scale graphene synthesis on Cu by chemical vapor deposition (CVD) has led to enormous interest worldwide over the past 14 years. The graphene CVD process involves flow of a carbon feedstock (typically methane) over a Cu surface

Ring-exchange interaction effects on magnons in the Dirac magnet CoTiO3

May 21, 2024
Author(s)
Yufei Li, Thuc Mai, Mohammed Karaki, Evan Jasper, Kevin Garrity, Chase Lyon, Daniel Shaw, Timmothy DeLazzer, Adam Biacchi, Rebecca Dally, Daniel Heligman, Jared Gdanski, Tehseen Adel, Maria Munoz, Alex Giovannone, Amit Pawbake, Clement Faugeras, Jeffrey Simpson, Kate Ross, Nandini Trivedi, Yuanming Lu, Angela R. Hight Walker, Rolando Valdes Aguilar
In magnetically ordered materials with localized electrons, it has been known for a long time [1–3] that the fundamental interactions are due to exchange of electrons. In most cases only the interaction between pairs of spins in neighboring atoms is taken

SHINERS Study of Chloride Order-Disorder Phase Transition and Solvation of Cu(100)

January 3, 2024
Author(s)
Thomas P. Moffat, David Raciti, Angela R. Hight Walker, Eric J. Cockayne, John Vinson, Kathleen Schwarz
Shell-isolated Nanoparticle Enhance Raman Spectroscopy (SHINERS) and Density Functional Theory (DFT) are used to probe Cl- adsorption and the order-disorder phase transition associated with the c(2×2) Cl- adlayer on Cu(100) in acid media. A two-component 

Noncryogenic Air Separation using Aluminum Formate Al(HCOO) 3 (ALF)

May 3, 2023
Author(s)
Dinesh Mullangi, Hayden Evans, Taner N. Yildirim, Yuxiang Wang, Zeyu Deng, Zhaoqiang Zhang, Thuc Mai, Fengxia Wei, John Wang, Angela R. Hight Walker, Craig Brown, Dan Zhao, Pieremanuele Canepa, Anthony K. Cheetham
Separating oxygen from air to create oxygen-enriched gas streams is a process that is significant in both industrial and medical fields. However, the prominent technologies for creating oxygen-enriched gas streams are both energy and infrastructure

Thermosensitivity Through Exchange Coupling in Ferrimagnetic/Antiferromagnetic Nano-Objects for Magnetic Based Thermometry

March 6, 2023
Author(s)
Frank Abel, Eduardo De Lima Correa, Adam Biacchi, Thinh Bui, Solomon I. Woods, Angela R. Hight Walker, Cindi L. Dennis
Temperature is a fundamental physical quantity important to the physical and biological sciences. Measurement of temperature within an optically inaccessible three-dimensional (3D) volume at microscale resolution is currently limited. Thermal magnetic

The Impact of Carbon Nanotube Length and Diameter on their Global Alignment by Dead-End Filtration

December 22, 2022
Author(s)
Christopher Rust, Pavel Shapturenka, Manuel Spari, Andreas Bacher, Qihao Jin, Han Li, Markus Guttmann, Ming Zheng, Tehseen Adel, Angela R. Hight Walker, Jeffrey Fagan, Benjamin Flavel
Dead-end filtration on polyvinylpyrrolidone-coated polycarbonate track-etched membranes has proven to be an effective method to prepare macroscopically (3.8 cm²) aligned thin films from solution-based single-wall carbon nanotubes (SWCNTs). However, to make

Elemental excitations in MoI3 one-dimensional van der Waals nanowires

November 28, 2022
Author(s)
Fariborz Kargar, Zahra Barani, Nicholas Sesing, Thuc Mai, Topojit Debnath, Huairuo Zhang, Yuhang Liu, Yanbing Zhu, Subhajit Ghosh, Adam Biacchi, Felipe H. da Jornada, Ludwig Bartels, Tehseen Adel, Angela R. Hight Walker, Albert Davydov, Tina Salguero, Roger Lake, Alexander Balandin
We report the polarization-dependent Raman spectrum of exfoliated MoI3, a van der Waals material with a "true one-dimensional" crystal structure that can be exfoliated to individual atomic chains. The temperature evolution of several Raman features reveals

Control of the Schottky barrier height in monolayer WS2 FETs using molecular doping

August 26, 2022
Author(s)
Siyuan Zhang, Hsun-Jen Chuang, SON LE, Curt A. Richter, Kathleen McCreary, Berend Jonker, Angela R. Hight Walker, Christina Hacker
The development of processes to controllably dope two-dimensional semiconductors is critical to achieving next generation electronic and optoelectronic devices. Understanding the nature of the contacts is a critical step for realizing efficient charge

Polyoxovanadates as Precursors for the Synthesis of Colloidal Multi-Metal Oxide Nanocrystals

March 31, 2022
Author(s)
Adam Biacchi, Lucas Johnson, Ashley Sweet, Eric Cal, Angela R. Hight Walker, Matthew Buck, Luke Barrante
Colloidal multi-metal oxide nanocrystals that contain the element vanadium are attractive materials for enabling diverse technologies. Few nanocrystal systems are synthetically well-developed, however, which is attributable to a scarcity of molecular

Influence of Dimensionality on the Charge Density Wave Phase of 2H-TaSe2

March 23, 2022
Author(s)
Sugata Chowdhury, Albert Rigosi, Heather Hill, David B. Newell, Angela R. Hight Walker, Francesca Tavazza, Andrew Briggs
Metallic transition metal dichalcogenides like tantalum diselenide (TaSe2) exhibit exciting behaviors at low temperatures including the emergence of charge density wave (CDW) states. In this work, density functional theory (DFT) is used to classify the

Synthesis, crystal structure, and physical properties of BaSnS2

February 11, 2022
Author(s)
Wilarachchige Gunatilleke, Andrew May, Angela R. Hight Walker, Adam Biacchi, George Nolas
Phase-pure BaSnS2, with space group Pn21/c, was synthesized and the structural and physical properties were investigated. The thermal properties and optical measurements are reported for the first time. The Debye temperature and Sommerfeld coefficient were

Dependence of Single-Wall Carbon Nanotubes Alignment on the Filter Membrane Interface in Slow Vacuum Filtration

January 22, 2022
Author(s)
Jeffrey Fagan, Angela R. Hight Walker, Adam Biacchi, Andrei Kolmakov, Zia Macdermid, William D. Rice, Joshua Walker, Thomas Searles
The recent development of slow vacuum filtration (SVF) technology has shown great promise for reproducibly producing high-quality, large-area aligned films of single-wall carbon nanotubes (SWCNTs) from solution-based nanotube dispersions. In contrast to

Advanced characterization of magnetization dynamics in iron oxide magnetic nanoparticle tracers

January 5, 2022
Author(s)
Thinh Bui, Adam Biacchi, Brianna Bosch Correa, Cindi L. Dennis, Weston L. Tew, Angela R. Hight Walker, Solomon I. Woods
Characterization of the magnetization dynamics of single-domain magnetic nanoparticles (MNPs) is important for magnetic particle imaging (MPI), magnetic resonance imaging (MRI), and emerging medical diagnostic/therapeutic technologies. Depending on