Mo-containing diamond-like carbon films with blue emission

Molybdenum-containing diamond-like carbon (Mo-DLC) thin films were synthesized on silicon substrate using metal cathodic arc and acetylene dual plasma deposition. Microstructural observations show that fine γ-MoC nanocrystallites with sizes of 1-2 nm are embedded in amorphous carbon cross-linked structures. The Mo-DLC films were found to have a photoluminescence (PL) band in blue. Due to obvious PL spectral asymmetry, we Gaussian divided the PL peak into two bands with the peak positions at about 405 and 455 nm. Spectral analyses suggest that the two blue PL bands arise from sp2 hybridized carbon clusters with different sizes and γ-MoC nanocrystallites. Our experimental results provide the understanding of the blue-emitting properties of metal-containing diamond-like carbon films.