Electrical Transport in “Few-Layer Graphene” Film Prepared by the Hot-Spray Technique: The Effect of Thermal Treatment

Abstract

We investigate charge transport of a randomly stacked few-layer graphene (FLG) film supported on quartz plate, as-prepared and after annealing treatment. The film is prepared by a simple, cheap and rapid hot spray technique from a FLG suspension, while FLG was obtained in our previous report by high yield mechanical exfoliation of pencil lead. According to Hall Effect measurements, the annealing process has strong impact on the conductivity of the FLG film, despite its low oxygen/defect content as confirmed by X-ray photoelectron spectroscopy (XPS), Raman, and photoluminescense spectroscopy. The nonohmic behavior along with a sheet resistance (R□) decreases from a few tens to a few kilo-ohms is observed for the FLG film, whereas after thermal treatment, a constant R□ of 0.7 kΩ is recorded. The improvement of conductivity in the FLG film is attributed mainly to desorption of toluene from the FLG surface according to the TPD-MS analysis and not only to the oxygen decrease as generally reported.