Characterization of Few-Layer Graphene on Stretchable Substrate Using Thermally-Treated Exfoliation

Abstract

thin layer of gluelike PMMA, onto a stretchable substrate. It obtained a large, high-quality layer of graphene printed on the flexible substrate by using our proposed thermallytreated exfoliation technique. Aluminum (Al) film with a thickness of 100 nm was thermally deposited over the transparent PEN substrate using a metal mask in order to gather accurate signals of Raman spectra. We measured the Raman spectra to identify the presence of FLG. The Raman data were obtained using 514-nm argon-ion laser excitation at room temperature. Figure 2 shows the comparison of the 514 nm Raman spectra between the FLG and PMMA layer. The most prominent features in the Raman spectra as were also seen in other studies, 8,15,16 i.e., G band at ~1580 cm �1 and a band 2D band at ~2700 cm �1 : the 2D peak of the FLG formed by a single Lorentzian peak. The two peaks are enough data to prove the presence of the FLG. The PMMA did not show a peak in the Raman spectra. Prior to obtaining the Raman spectra above, we tried to get the Raman data of the graphene on PMMA layer, but without Al film, meaning the sample was entirely transparent. The Raman spectra we captured were out of the range that can be analyzed. The main cause is that the argon laser goes through the sample without any scattering. Thus, the layer to block the laser is needed to get the Raman spectra of the graphene. In addition to the Raman spectra analysis, the atomic force microscopic (AFM) measurement was performed in order to confirm the thickness of the FLG on the PMMA layer, since the number of the graphene layer can be estimated by the thickness.