Raman spectra of the DLC:Cr films deposited at
5/5 and 10/10 of the C2H2/Ar flows appear broad peak in the range
from 800 to 2000 cm−1 which confirms that the films are amorphous.
The peak position of G-band centered around 1560 cm−1
and the peak position of D-band centered around 1351 cm−1, all
show a downshift as compared with the polycrystalline graphite
structure (G-band = 1580 cm−1, D-band = 1360 cm−1). This suggests
that the films are of diamond-like structure [20]. With increasing
the C2H2/Ar flow, the Raman spectra has a low intensity at high
C2H2/Ar flows, as shown in Fig. 1c and d, which may be due to
the fact that a large amount of the carbon atoms are bonded with
Cr to form chromium carbides so that the amount of graphite-like
or diamond-like bonds in the films is disappeared