Realization of good quality bilayer graphene by single step laser ablation process

Abstract

We report on a versatile technique for the synthesis of graphene on a Si /SiO2 (300 nm) substrate by laser ablation. A direct method for the synthesis of graphene in the liquid phase using a pulsed laser has added advantages. There is a possibility of employing various substrates without the involvement of defect inducing chemicals that are introduced during the transfer process of graphene films. Pulsed KrF laser at 248 nm with laser fluence between 2.5 J/cm2 to 3.75 J/cm2 was employed to obtain highly crystalline graphene layers from a commercially obtained graphite bar instead of expensive highly oriented pyrolytic graphite (HOPG). The crystalline quality was confirmed by selected area electron diffraction (SAED) pattern. The de-convolution of the 2D peak in the Raman spectrum suggests the existence of bilayer graphene. A systematic study on the Raman spectra of graphite target and the evolution of graphene is presented and discussed.