Preparation And Raman Spectroscopy Investigation Of Few-layer Graphene

Graphene is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, and can travel for micrometers without scattering at room temperature. These unique properties hold great promise for potential applications in nanoelectronics. In this paper, few-layer graphene was prepared by micromechanical cleavage and reduction of GO, respectively. The structure of the sample were characterized systemly by Raman spectroscopy.Single- and few-layer graphene taken from freshly cleaved HOPG surfaces by the scotch-tape technique can be readily transferred on to silicon wafer. It is interesting that single-layer graphene placed on a Si wafer with a 300nm thick layer of SiO2 becomes visible in an optical microscope. Results of Raman and optical microscopy measurement showed that few-layer graphene was presence.GO were produced using a modified Hummers' method from high-purity graphite powder. It was found that graphite were oxided completely, which was demonstrated by Raman spectroscopy and XRD. Dispersions of GO was carried out in water and NMP, respectively. It was found that GO can be dispersed uniformly.Herein, hydrothermal dehydration by using of teflonlined autoclave and hydrazine were used to reduced GO. It is found that hydrothermal dehydration had a better effect on reduction of GO compared to hydrazine. Dispersions of GO-reduced was also carried out in water and NMP, respectively. It was found that GO-reduced can not be dispersed in warer by bath ultrasonication and it may be because of hydrophilic groups' absent on GO.PL spectra of the sample showed that the luminescence of GO and GO-reduced were found to occur in the visible wavelengths range.Raman spectroscopy can be used as a quick, lossless and unambiguous method to determine the number of graphene layers. It has also played an important role in the structural characterization of GO.