Noise and Thermal Characterization of Exfoliated Graphene Films

Electrical conductivity of graphene films is perhaps the best indication to show the extent of the basal plane and the quality of surface achieved. On the other hand, the liquid phase exfoliation has been a promising route to achieve mass production of graphene for potential applications including nanoelectronic devices, sensors, electrochemical energy storage and conversion systems, electronics components, nano-composites and biotechnology. In the present work, Exfoliated Graphene Films (EGFs) were obtained by a rapid exfoliation procedure using sonication treatment with solvent 1-Methyl-2-pyrrolidinone (NMP) and natural graphite flakes as precursor material. The obtained suspension was stable for a long time, and its quality was evidenced by SEM, Raman Spectroscopy, TEM and UV-visible analyses. Moreover, some Electrical Characterizations Test (ECT) were performed on EGFs deposited on IDE (Inter Digitized Electrodes). These measurements were made at room temperature before and after a thermal treatment in order to dry and evaporate the solvent. Furthermore, Low-Frequency Noise Measurements (LFNMs) were performed to verify the noise characteristic of EGFs, before and after thermal treatment. The results showed that the film resistivity (Rf) was around 14.8x103Ω, and it decreases with increasing temperature. Moreover, LFNMs results showed a noise spectrum S(f)~1/fα (where f is the frequency and α is compressing between 0.9 and 1.2). Also ours results demonstrated that the noise level was enhanced after thermal treatment, while the spectrum pattern was maintained.