Preparation of Large-Scale CoS2 Nanowires and their Raman Study

Structurally sound self-growing large-scale CoS2 nanowires were synthesized via a template-free and catalyst thermal sulfurization process on Co films. After annealing cobalt thin films in pure sulfur (S) vapor produced large area of CoS2 nanowires, we observe symmetrical and vertically alligned nanowires on the thin film surface. After running the thermal treatment in static S atmosphere, the cobalt thin film is converted into polycrystalline CoS2 nanowires and CoS2 film. We recorded the form of the CoS2 nanowires after the cobalt thin film was annealed. We also investigated the influence of the film annealing time and temperature. Aligned and long nanowires can be effectively formed at a temperature of around 400 °C for 5-10 h. The diameter of the CoS2 nanowires is around 10 nm with a length of ~ 2 µm. In addition, the Raman spectra of isolated CoS2 nanowired were lso studied.

Synthesis, structural and nanomechanical properties of cobalt based thin films

Purpose – The purpose of this paper is to produce cobalt (Co)-based thin films by metalorganic chemical vapor deposition (CVD) technique and then to evaluate structural and mechanical integrity. Design/methodology/approach – Co-based thin films were produced by metalorganic CVD technique. Boronizing, carburization and nitridation of the produced Co thin films were accomplished through a post-treatment stage of thermal diffusion into as-deposited Co thin films, in order to produce cobalt boride (Co2B), cobalt carbide and cobalt nitride thin films in the surface layer of Co. The surface topography and the crystal structure of the produced thin films were evaluated through scanning electron microscopy and X-ray diffraction, respectively. The mechanical integrity of the produced thin films was evaluated through nanoindentation technique. Findings – The obtained results indicate that Co2B thin film exhibits the highest nanomechanical properties (i.e. H and E), while Co thin film has enhanced plasticity. The cobalt oxide thin film exhibits higher resistance to wear in comparison to the cobalt thin film, a fact that is confirmed by the nanoscratch analysis showing lower coefficient of friction for the oxide. Originality/value – This work is original.