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Code:
ThOD
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Time Slot/Poster Number:
10:30 -11:00 am
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Session:
Carbon-Based Materials II
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Raman Spectroscopy to Study Disorder and Perturbations in sp2 Nano-Carbons
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| Ado Jorio1; Luiz Gustavo Cancado1; Erlon H. Martins Ferreira2; Fernando Stavale2; Carlos A. Achete2; Marcus V. O. Moutinho3; Rodrigo B. Capaz3
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1Federal University of Minas Gerais, Belo Horizonte/Mg, Brazil; 2Inmetro, Rio de Janeiro, Brazil; 3UFRJ, Rio de Janeiro, Brazil
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| View Abstract PDF |
| Summary |
We have studied the defect-induced double-resonance processes in graphene. The understanding of the evolution of disorder-induced effects is advanced by combining Raman experiments with microscopy, thus making it possible to develop new theoretical models. The double-resonance process describes, based on the electron and phonon dispersion relations, the frequencies of the disorder-induced Raman peaks and their dependence with the excitation laser energy, as described previously [1]. Here the disorder-induced peak intensities are discussed, i.e. how they evolve with increasing amount of disorder.
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Code:
ThOD
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Time Slot/Poster Number:
11:00 - 11:30 am
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Session:
Carbon-Based Materials II
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Unique One- and Two-Dimensional Phenomena Observed in Carbon Nanotubes and Graphene
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| Stephen Cronin; Adam Bushmaker
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University of Southern California, Los Angeles, CA
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| View Abstract PDF |
| Summary |
In this work, Raman spectroscopy is used to measure individual, suspended CNTs under applied gate and bias potentials. Our ability to fabricate nearly defect-free, suspended carbon nanotubes (CNTs) has enabled us to observe several phenomena never seen before in CNTs, including breakdown of the Born-Oppenheimer approximation, mode selective electron-phonon coupling, leading to negative differential resistance (NDR) and non-equilibrium phonon populations, and a Mott insulator transition. Raman spectroscopy of periodic ripple formation in suspended graphene will also be reported. As will be shown, preparing clean, defect-free devices is an essential prerequisite for studying the rich low-dimensional physics of CNTs and graphene.
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Code:
ThOD
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Time Slot/Poster Number:
11:30 - 11:50 am
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Session:
Carbon-Based Materials II
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Barometrically and Electrostatically Induced Strain in Suspended Graphene
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| Sebastian Remi1; Alexander Kitt1; Anna Swan1, 4; Bennett B. Goldberg1, 4; Ben Feldman3; Jens Martin3; Amir Yacoby3; Ji Won Suk2; Rodney S. Ruoff2
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1Boston University, Physics Department, Boston, MA; 2The University of Texas, Austin, TX; 3Harvard University, Cambridge, MA; 4Boston University, ECE, Boston, MA
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| View Abstract PDF |
| Summary |
We induce uniaxial and biaxial strain in suspended graphene by applying electrostatic or Barometric forces and the effects on the Raman spectrum are measured. Youngs modulus and Grüneisen parameters can be determined from the splitting and shifts of Raman phonon frequencies. Due to our sample geometry substrate dependent perturbations can be minimized.
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Code:
ThOD
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Time Slot/Poster Number:
11:50 am - 12:10 pm
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Session:
Carbon-Based Materials II
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Modifying properties of graphene – a Raman microscopic study
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| Ze Xiang Shen
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Nanyang Technological University, Singapore, Singapore
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| View Abstract PDF |
| Summary |
Raman spectroscopy is an important tool for nano carbon materials study due to its resonance behavior. In this talk, we will present our Raman imaging study of graphene: determination of graphene thickness and graphene axes; and folded graphene sheets. Many unique properties of graphene are accorded to single layer graphene (SLG). However it is very difficult to fabricate large single crystalline SLG samples. We will also present our results in modifying few-layer graphene (FLG) samples so that they have similar properties as that of SLG, as well as modifying edge chirality, intercalation, hydrogenation, and studies of graphene with mis-oriented layers.
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Code:
ThOD
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Time Slot/Poster Number:
12:10 - 12:30 pm
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Session:
Carbon-Based Materials II
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Curved Nanocarbons: Probing the Curvature and Topology Effects Using Phonon Spectra
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| Sanju Gupta1; Avadh Saxena2
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1University of Pennsylvania, Philadelphia, PA; 2Los Alamos National Laboratory, Los Alamos, NM
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| View Abstract PDF |
| Summary |
In spite of detailed structural characterization of nanoscale carbons, they still possess some features that are not entirely understood particularly in terms of topological characteristics. By means of resonance Raman spectroscopy, we elucidated the notion of global topology and curvature by determining the prominent Raman bands variation for various carbon nanostructures including tubular (single, double- and multi-walled nanotubes, peapod), spherical (hypo- and hyper-fullerenes, onion-like carbon) and complex (nanocones, nanohorns, nanodisks and nanorings) geometries. This knowledge points to an unprecedented emergent paradigm of global topology/curvature->property->functionality relationship.
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