All spectra show characteristic G, 2D and D peaks, at ~1580 cm -1 , ~2670 cm -1 and ~1330 cm - 1 , as indicated in Fig. . The intense G band represents the ordered graphitic structure of sp 2 carbons , while the D band indicates the structural defects . The intensity ratio of D peak and G peak (ID/IG) increased from 0.98 ± 0.26 (EEG) to 1.33 ± 0.21 (EEA), indicating the increased level of disorder introduced by the covalent bonding (functional groups) during the silane functionalization procedure. Meanwhile, the full-width at half-maximum of 2D peaks (FWHM (2D)) increased from 79 cm -1 (EEG) to 84 cm -1 (EEA), as a result of peaks broadening with increasing defects . The TEM bright field images and corresponding selected area electron diffraction (SAED) patterns (Fig. ) indicate that the EEG flakes vary from fewlayer to many layer graphene sheets, both with wrinkled morphology. The SAED pattern of the thin EEG flake demonstrated clear six-fold symmetry owing to the hexagonal structure of carbon atoms, while for the thick flake, ring-like structures appeared due to the higher stacking disorder .