Surface Functionalization of Substrate-Transferred Graphene for Electronic Applications

The quality of graphene may be of utmost importance for various applications in electronics demanding perfect electric contacts as well as for many topics of physical research. However, atomic-scale exploration reveals the presence of organic residues which were introduced during the transfer process of the graphene layer from the substrate of growth (mostly metallic ones) onto the dielectric substrates required in electronics. Organic contamination can also be generated during experiments, as well as by atmospheric influence during storage. We explored the elimination of these unwanted layers (which are undetectable by the usual Raman spectroscopy) via treatment at various temperatures and vacuum levels. Comparative diagnostics were performed via AFM, with the best results obtained in samples treated near 400 °C.