A homogeneous diamond-like film was obtained on an area of 75 × 25 mm2. Study of the film structure, using transmission electron microscopy and Raman spectroscopy, showed a mixture of carbon atoms with sp2- and sp3-bonds. Structure of carbon film is determined by the presence of randomly oriented carbon clusters bound by diamond sp3-bonds (tetrahedral amorphous carbon, ta-C). Electron diffraction patterns demonstrate strongly distorted interfacial distances. Raman spectra show that there are carbon atoms with graphite sp2-bonds in the film, but a signal of graphite crystal lattice is absent in electron diffraction: This implies that hexagonal units are not shaped into a graphite crystal lattice. Broad D-band in Raman spectra shows strongly distorted carbon bonds in graphite. If diamond phase dominates, the space between diamond clusters is filled with carbon atoms with sp2-bonds (turbostratic structure). Thus, diamond areas are bound into a single discontinuous aggregate of carbon diamond-like film.
- Amorphous carbon
- Pulsed laser deposition
- Vibrational properties characterization