Hard Si–N–C films with a tunable band gap produced by pulsed glow discharge deposition

The tuning of the optical band gap in the range of ETauc=0.96–4.31 eV was demonstrated in the Si–N–C films grown by pulsed glow discharge deposition. The films were grown at room temperatures from the following precursor gases: silane (SiH4), nitrogen (N2), and acetylene (C2H2). The stoichiometry of the films was varied by changing the flow of acetylene gas in the deposition chamber. The properties of the films were characterized using Rutherford backscattering (RBS), Elastic Recoil Detection analysis (ERD), profilometry, nanoindentation, UV–visible and infrared spectroscopies. All films demonstrated high hardness between 11.6 and 15.6 GPa, which makes them a valuable material for technologies requiring hard scratch resistant coatings with a tunable band gap.