Surface enhanced Raman scattering (SERS) investigation of amorphous carbon

Surface enhanced Raman scattering (SERS) was applied to study hydrogenated amorphous carbon (a-C:H) and amorphous carbon (a-C) samples. Carbon free silver colloid served as SERS active medium; it was dried on the sample surface. The Raman signal amplitude increase by order of magnitude was observed. Further enhancement was recorded on the Raman spectrum as a result of the blinking phenomenon, which took place applying certain measurements conditions. A number of reproducible peaks was observed in the D and G band region both for a-C:H and a-C. Coexistence of these peaks in one sample's spectrum indicates that the amorphous carbon D and G peaks consist of several components: they are inhomogeneously broadened. For a given amorphous carbon sample the shape of the conventional Raman spectrum is determined by vibrations of dominant structural units. SERS gives the possibility to identify these units; moreover, presence of other components, not so characteristic for the sample, also can be evaluated. (C) 2004 Elsevier B.V. All rights reserved.