H. Wilhelm et al., Raman spectroscopic studies on well-defined carbonaceous materials of strong two-dimensional character, J APPL PHYS, 84(12), 1998, pp. 6552-6558
Using 514 nm radiation and a careful experimental protocol allowing us to m
ake quantitative intensity analyses, we have examined the first- and second
-order Raman spectra of five varieties of graphite. These include single-cr
ystal graphite and highly oriented pyrolytic graphite as references, then t
wo with a significant content of c-axis translation faults introduced throu
gh grinding and exfoliation, and a last sample which is purely turbostratic
. We show that full c-axis stacking disorder results in a strong increase o
f the scattered E-2g-mode intensity. We have further shown that even in tho
se strongly disordered stacking sequences, but in which the AB sequence per
sists over only a few layers, the doublet around 2700 cm(-1) is resolved. W
e argue against assigning the peak around 1355 cm(-1) to "disorder,'' as is
so often done, but to the finite in-plane domain size as proposed a number
of years ago; moreover, we suggest that this peak is a more sensitive prob
e of such small domains than is x-ray diffraction. (C) 1998 American Instit
ute of Physics. [S0021-8979(98)00124-8].