Blue Emission from Mo-Doped Diamond-like Carbon Films Fabricated by Dual Plasma Deposition

Metal-containing diamond-like carbon (DLC) films have attracted a great deal of scientific interest because of their favorable properties as bulk or thin film materials in many applications. Though DLC has gotten considerable attention as a promising material in electroluminescence devices, there have been few studies on the photoluminescence (PL) properties of metal-doped DLC films. In this work, molybdenum-doped DLC thin films were synthesized on silicon substrate using metal cathodic arc and acetylene dual plasma deposition. Microstructural investigations show that fine y-MoC nanocrystallites with sizes of 1 - 2 nm are embedded in the amorphous carbon cross-linked structure. The Mo-doped DLC films show a PL band in the blue region. Due to obvious PL spectral asymmetry, the PL peak can be deconvoluted into two bands with peak positions at about 405 and 455 nm, respectively. Spectral analyses suggest that the two blue PL bands arise from sp² hybridized carbon clusters with different sizes and y-MoC nanocrystallites, respectively. Our experimental results are important to the understanding of the blue light emitting properties of metal-containing DLC films.