Fabrication of Transparent Protective Diamond-Like Carbon Films on Polymer

Abstract

Si doped hydrogenated amorphous carbon (Si-DLC) films as a candidate protection coating for polycarbonate (PC) were prepared using a pulse-biased inductively coupled plasma chemical vapor deposition (ICP-CVD) system with a gas mixture of acetylene (C2H2) and tetramethylsilane [Si(CH3)4]. The effects of Si incorporation on the structure and optical properties of the Si-DLC films were investigated. In addition, plasma pretreatments with O2, N2, and Ar gases were carried out to enhance the adhesion strength of Si-DLC films on polycarbonate. Structural characterization through Raman and X-ray photoelectron spectroscopy (XPS) analyses showed that the incorporation of Si atoms in DLC films leads to an increase in the optical band gap (Eopt) with the formation of sp3 C–Si bonds. O2 plasma pretreatment improved the strength of adhesion of the Si-DLC films to polycarbonate, while Ar and N2 plasma treatments did not. This can be explained by the formation of an activated dense interfacial layer by O2 plasma pretreatment.