Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural analysis of polycrystalline graphene systems by Raman
  spectroscopy   A theoretical model supported by experimental results explains the dependence
of the Raman scattering signal on the evolution of structural parameters along
the amorphization trajectory of polycrystalline graphene systems. Four
parameters rule the scattering efficiencies, two structural and two related to
the scattering dynamics. With the crystallite sizes previously defined from
X-ray diffraction and microscopy experiments, the three other parameters (the
average grain boundaries width, the phonon coherence length, and the electron
coherence length) are extracted from the Raman data with the geometrical model
proposed here. The broadly used intensity ratio between the C-C stretching (G
band) and the defect-induced (D band) modes can be used to measure crystallite
sizes only for samples with sizes larger than the phonon coherence length,
which is found equal to 32 nm. The Raman linewidth of the G band is ideal to
characterize the crystallite sizes below the phonon coherence length, down to
the average grain boundaries width, which is found to be 2.8 nm. "Ready-to-use"
equations to determine the crystallite dimensions based on Raman spectroscopy
data are given.

16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th