Features of the vibrational spectra of diamond-like and polymer-like a-C:H films

Comparative analysis of the IR spectra of multiple frustrated total internal reflection (MFTIR) in the range 4000-1000 cm(-1) is performed for diamond-like and polymer-like a-C:H films with the refractive indices n >= 2.0 and n <= 1.7, respectively. The films are obtained by chemical-vapor deposition from octane, cyclohexane, toluene, and acetylene under various conditions using a dc glow discharge plasma. Characteristic features are found in the vibrational spectra of a-C:H films with different refractive indices. A peak at 1250 cm(-1), which is independent of the initial hydrocarbon, is observed in the spectra of the diamond-like films. Additional peaks at 3400 and 1700 cm(-1), due to O-H and C=H vibrations, are present in the spectra of the polymer-like films. It is shown that the integrated intensity of the band of CH vibrations peaked at similar to 2900 cm(-1) decreases exponentially by an order of magnitude with an increase in n from 1.55 to 2.4. (c) 2005 Pleiades Publishing, Inc.