Raman scattering spectroscopy of micrometer-sized carbon serpentines

The stability of carbon-based films is greatly influenced by their intrinsic stress and by the film-substrate interaction that, in certain cases, can induce the formation of micrometer-sized patterns. The study of these patterns (henceforth, C-serpentines) provides important information regarding the mechanical properties of C films and, hence, has motivated several investigations. However, most of these efforts originate from microscope based techniques in which the bond structure details of the C-serpentines are not taken into account. The importance of C-films in practical applications and the absence of Raman spectroscopy studies about C-serpentines form the basis of this paper. Accordingly, this work presents a thorough investigation of a C-film (as deposited by ion-beam deposition) onto the C-serpentine and nearby, as obtained by Raman scattering spectroscopy. Based on the experimental results it is possible to state that, contrary to the C-film (that is made of very small graphite crystallites), the regions occupied by the C-serpentine correspond to larger crystallites (typically >= 100 nm). Also, the results show that the C-serpentine is less stressed, which is in agreement with its crystallite size as well as with the accepted models that explain the C-serpentine formation.