Chemical vapour deposited graphene: substrate pre-treatment, growth and demonstration as a simple graphene-based SERS substrate

In chemical vapour deposition (CVD) of graphene, surface roughness and purity of the copper substrate are very crucial for obtaining uniform films. Even though electrochemical polishing is an effective technique for obtaining homogeneous graphene films, most of the experiments adopt complex experimental parameters like electrolyte heating, stirring and use of additives for better results. These are not applicable to thin copper foils used in CVD of graphene. In the present study, a simple electrochemical procedure is developed for deposition of high-quality graphene films with good coverage. The depositions of graphene films on bare and polished copper foils for the same growth conditions are analysed using various microscopic techniques. The uniformly grown graphene on copper is then directly employed as a surface-enhanced Raman scattering (SERS) substrate along with plasmonic silver nanoparticles. A simple SERS substrate having a reasonable detection limit of 10 − 10 M for R6G is achieved with uniform SERS signals over a large area. The homogeneity of SERS substrate can be attributed to the uniformity of the deposited graphene film. A simple and efficient SERS substrate using conventional methods is achieved through the incorporation of chemical vapour deposited graphene. The study covers the growth of CVD graphene film starting from substrate pre-treatment, various analyses of the film and finally the application in SERS. (author)