  Raman spectroscopy has been employed to distinguish between the Raman
spectrum of pristine hydrogenated diamond like carbon (PHDLC) and that of
electrochemically hydrogenated diamond like carbon (ECHDLC). The enhancement of
the background photoluminescence (PL) in the Raman spectrum and broadening of
PL spectrum of ECHDLC are identified to be due to increase of sp3 C-H density
onto the PHDLC surface, during novel electrochemical process of hydrogenation
of sp2 C=C into sp3 C-H.
