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Raman spectroscopic studies of pulsed laser-induced defect evolution in graphene


Correspondence to: Satyaprakash Sahoo and Ram S. Katiyar, Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931, USA. E-mail:;


Raman spectra were obtained for graphene after irradiating the samples by pulsed laser (λ = 248 nm). Changes in the spectra were observed as the pulse laser energy density (PLED) was varied from 0.1 to 0.25 J/cm2. Changes in bilayer graphene were accompanied by the appearance of the D peak and the broadening of the G peak. Changes in multilayer graphene are more profound as the Raman spectra changes from a multilayer to bilayer and subsequently to monolayer graphene in response to a slow increase in the PLED. The threshold PLED was found to be dependent on the number of graphene layers. We also irradiate graphene with very high PLED (much above the threshold), and the Raman spectra were found to be significantly changed. The G-band became broader, and red shifted, while the intensity of the 2D-band was drastically reduced and an intense defect-related D peak appeared at about 1350 cm−1. The laser ablation of graphene, both with low- and high-energy intensity, is consistent with the reported theoretical predictions. Copyright © 2013 John Wiley & Sons, Ltd.