Mahajan, Somna S; Barshilia, H C; Mehta, B R; Vankar, V D
Carbon; Chemical vapour deposition; Ellipsometry; Optical properties
The carbon bonding ratio in diamond-like carbon (DLC) thin films has been estimated from the ε2 spectra obtained by spectroscopic ellipsometry. A method has been developed to find out the atomic fractions of sp3- and sp2-bonded carbon atoms by combining the various features of the existing methods. The atomic fraction of sp2-bonded carbon atoms has been determined by fitting the gaussian curves in the experimentally observed ε2, spectra in the low energy range (< 4 eV). The atomic fraction of sp3-bonded carbon atoms has been determined by calculating the total electron density in the DLC matrix. The amount of hydrogen present in DLC films has also been taken into account.