Contribution of sp3 clusters in films and fibers obtained from camphor

Considerable attention has been focused on the growth of carbon-based films or fibers by various methods. Diamond-like carbon (DLC) films may be of greater importance in some specific electronic applications such as flat panel displays, which represent a very large market. In this study, carbon-based thin films and fibers obtained from doped camphor soot were studied by confocal microRaman spectroscopy at 632.8 nm.Different contributions were identified between 1000 and 1650 cm⁻¹ in the Raman spectra of the as-grown and laser-annealed films and fibers. The contributions were the D-like and G-like peaks of polycrystalline graphite at about 1345 and 1530 cm⁻¹, respectively, with a FWHM value about 5 times larger than in a:C. It is now well established from correlation between Raman signature and grain size measurements that the width of the Raman line is a decreasing function of the graphite grain size. From these results, one can estimate that the grain size of this polycrystalline graphitic phase was small. An additional feature is observed at about 1240 cm⁻¹ which could be due to sp³-bonded carbon clusters.