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

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Displaying 76 - 100 of 352

Dielectric properties of Nb_x}W_1-x}Se_2} alloys

December 16, 2019
Author(s)
Albert Rigosi, Heather M. Hill, Sergiy Krylyuk, Nhan V. Nguyen, Angela Hight Walker, Albert Davydov, David Newell
The growth of transition metal dichalcogenide (TMDC) alloys provides an opportunity to experimentally access information elucidating how optical properties change with gradual substitutions in the lattice compared with their pure compositions. In this work

Polarization-resolved Raman spectroscopy of \alpha-RuCl3 and evidence of room temperature two-dimensional magnetic scattering

October 14, 2019
Author(s)
Thuc T. Mai, Amber D. McCreary, P. Lampen-Kelley, Nicholas P. Butch, Jeffrey R. Simpson, J.-Q. Yan, S. E. Nagler, D. Mandrus, Angela R. Hight Walker, Rolando Valdes Aguilar
Polarization-resolved Raman spectroscopy was performed and analyzed from large, high quality, mono-domain single crystal of \alpha-RuCl3, a proximate Kitaev quantum spin liquid. Spectra were collected with laser polarizations parallel and perpendicular to

Global alignment of solution-based single-wall carbon nanotube films via machine-vision controlled filtration

September 11, 2019
Author(s)
Jeffrey A. Fagan, Angela R. Hight Walker, Adam J. Biacchi, Joshua S. Walker, William D. Rice, Thomas Searles, Valerie A. Kuehl
Over the past decade, substantial progress has been made in the chemical processing (chiral enrichment, length sorting, handedness selectivity, and filling substance) of single- wall carbon nanotubes (SWCNTs). Recently, it was shown that large

Short-Range Charge Density Wave Order in TaS2

June 25, 2019
Author(s)
Jaydeep D. Joshi, Heather M. Hill, Sugata Chowdhury, Christos D. Malliakas, Francesca M. Tavazza, Utpal Chatterjee, Angela R. Hight Walker, Patrick M. Vora
2H-TaS2 undergoes a charge density wave (CDW) transition at T_CDW ~ 75 K, however key questions regarding the onset of CDW order remain under debate. In this study, we explore the CDW transition through a combination of temperature and excitation-dependent

Correlating anisotropic mobility and intermolecular phonons in organic semiconductors to investigate transient localization

March 19, 2019
Author(s)
Emily G. Bittle, Adam J. Biacchi, Lisa A. Fredin, Andrew A. Herzing, Thomas C. Allison, Angela R. Hight Walker, David J. Gundlach
Charge transport in organic semiconductors is governed by a mix of polaron hopping and band- like transport mechanisms. The energy of polaron hopping and formation are similar in magnitude to the energies of inter- and intra- molecular modes, which points

Metrological Assessment of Single-Walled Carbon Nanotube Materials by Optical Methods

March 1, 2019
Author(s)
Jeffrey A. Fagan, Angela R. Hight Walker, Ming Zheng, Lefebvre Jacques, Paul Finnie
This chapter discusses the metrology – i.e. the science of measurement – of single-wall carbon nanotubes (SWCNTs) with optical methods. Professor Mildred (“Millie”) Dresselhaus was a strong advocate for nanotube metrology and a pioneer in carbon nanotube

Raman Imaging of Surface and Sub-Surface Graphene Oxide in Fiber Reinforced Polymer Nanocomposites

March 1, 2019
Author(s)
Amber D. McCreary, Qi An, Aaron M. Forster, Kunwei Liu, Siyao He, Chris Macosko, Andreas Stein, Angela R. Hight Walker
The incorporation of nanofillers, such as graphene oxide (GO) into fiber reinforced polymer composites to improve their mechanical properties is a significant research area for a variety of industrial applications. However, to date there is no reliable

Defect Evolution of Ion-Exposed Single-Wall Carbon Nanotubes

January 3, 2019
Author(s)
Jana Kalbacova, Elias J. Garratt, Raul D. Rodriguez, Angela R. Hight Walker, Kevin A. Twedt, Jeffrey Fagan, Teresa I. Madeira, Jabez J. McClelland, Babak Nikoobakht, Dietrich R. Zahn
A systematic evaluation of defects is essential to understand and engineer device properties and applications. Raman spectroscopy is employed for the characterization of carbon nanomaterials in particular to quantitatively evaluate defects from the

Utilizing confocal laser scanning microscopy for rapid optical characterization of graphene

November 20, 2018
Author(s)
Vishal Panchal, Yanfei Yang, Guangjun Cheng, Jiuning Hu, Mattias Kruskopf, Chieh-I Liu, Albert Rigosi, Christos Melios, Angela R. Hight Walker, David B. Newell, Olga Kazakova, Randolph Elmquist
Confocal laser scanning microscopy (CLSM) is a non-destructive, highly-efficient optical characterization method for large-area analysis of graphene on different substrates, which can be applied in ambient air, does not require additional sample