Bonding properties of hydrogenated amorphous carbon thin films characterized by fourier transform infra-red spectrometer

Abstract

This paper reports a study of structural properties of hydrogenated amorphous carbon (a-C:H) thin films using infrared (IR) absorption. The samples were prepared on corning glass substrate using a direct-current plasma enhanced chemical vapor deposition (DC-PECVD) technique. The deposition time was fixed at 5 hours. The infrared absorption was taken in the stretching frequency ranges from 2700-3200cm(-1) to identify the relevant CH bonding. The measured spectrums were observed to be in wavy-like curves associated with sp(m) CH(n) configuration with m, n =1-3. The spectrum showed gradually disappearing with increasing power, w (0.2989-0.4218 W) as the film properties ranges from polymer-like (PAC) to graphite-like (GAC). The curve measured at 0.2989 W indicated marked changes with detectable infrared absorption rates in a-C:H at 2959cm(-1), 2934cm(-1) and 2872cm(-1) (polymer-like structures, PAC). These correspond to the presence of sp(3) CH(3) (symmetric and asymmetric), sp(3) CH(2) (asymmetric) and sp(3) CH.