Insight of cleaning, doping and defective effects on the graphene surface by using methanol

Graphene has attracted enormous interest to researchers because of its remarkable electrical, mechanical, and optical properties. Chemical vapor deposition (CVD) method was used to synthesize the graphene. The methanol (CH3OH) was used to investigate the cleaning, doping and defective effect in the graphene surface. The samples were characterized by X-ray diffraction patterns (XRD), field emission scanning electron microscope (FESEM) images, Xray photoelectron spectroscopy (XPS) measurements, and Raman spectroscopy. XRD indicates the introduction of oxygen in graphene layer. FESEM images of samples suggest the sheet like morphology. XPS measurements confirm the existence of large number of oxygen containing functional groups (C=O, COOH, and CO) and C-C in the graphene surface. The Raman spectra confirm the n-doping and cleaning effects on graphene surface through the red shifts of G and 2D peaks. Furthermore, the optical images were used to observe the residues in graphene. The residues are obtained due to adsorption of CH3OH in graphene surface. Therefore, this work provides a simple and effective approach to investigate the cleaning, doping and defective effects on the surface of graphene using CH3OH solvent that can be applied in tunable electronic devices and gas sensor.