Ultraviolet Raman characterisation of diamond-like carbon films

Diamond-like carbon (DLC) films with a range of sp(3) fractions have been examined by ultraviolet (UV) spectroscopy with 244 nm excitation. The UV Raman spectra of both hydrogenated and unhydrogenated films show the G peak near 1600 cm(-1) and a broad peak around 1200 cm(-1), which is attributed to C-C stretching vibrations of sp(3) sites. It is found that the ratio of the intensities of the C peak and the 1200 cm(-1) peak follows a universal dependence with the sp(3) content in both hydrogenated and unhydrogenated DLCs. This can be used for non-destructive evaluation of the sp(3) content of any DLC film