and the in-plane crystal size La obtained from x-ray data [9,10]. The
linear relationship shows that the Raman intensity is proportional
to the percentage of “boundary regions” in the sample. Moreover,
the intensity ratio provides a quantitative description of the carbon
microstructure, and is easily evaluated for each sample through
a Gaussian curve-fitting algorithm. For example, for laser Raman
studies of carbon films, intensity ratios are between 0.4 and 2.5 and
correspond to in-plane crystal sizes between roughly 1.8 and
11.0 nm [11]. Diamond can be characterized by a narrow band at
1332 cm1, corresponding to three times degenerated vibration of
the symmetry of T2g. Intermediate phases DLC (Diamond-Like
Carbon) and amorphous carbon are represented by wide D and G
bands [12].