Abstract
In this work,we report a method to improve the efficiency of the micromechanical cleavage technique to obtain few-layers graphene samples, from natural graphite flakes, which were previously submitted to two chemical treatment times with H2SO4(17 and 25 hours). After the chemical treatment times, Raman spectroscopy reveals a hydrogenation of the few-layer graphene samples, which were obtained from the treated graphite flakes. To analyze the hydrogenation of the samples, the G and 2D bands of the Raman spectra of the treated and un-treated samples were analyzed and compared, as well as the I(2D)/I(G) ratio, revealing a p-doping on the treated samples when compared with the untreated samples. Our studies could be of great importance to obtain larger and greater amount of few-layer graphene samples.
Highlights
Graphene, by its fabulous mechanical, electronic, thermal and optical properties, is one of the most promising candidates for the generation of electronic materials [1]
In order to analyze the surfactant effect of the chemical treatment on graphite G0, which directly affects the number of samples obtained on each substrate, the number of layers (n) and type of doping on the samples were determined by Raman spectroscopy, using a spectrometer Jobin Yvon T64000 with a spectral resolution of 1 cm−1, in a simple mode with a grid of 1800 lines
We conclude that the chemical treatment of graphite flakes with H2SO4 produces a significant improvement on the micromechanical cleavage method, increasing considerably the efficiency to obtain few-layer graphene samples
Summary
By its fabulous mechanical, electronic, thermal and optical properties, is one of the most promising candidates for the generation of electronic materials [1]. Interaction between the adjacent layers) to obtain individual layers of graphene [14] This effect can take advantage to increase the efficiency of the micromechanical cleavage technique in the preparation of few-layer graphene samples. The hydrogenated graphene was experimentally studied by Raman spectroscopy and the main reported characteristics were: 1) The G band position increases for increasing ǀEFǀ and saturates for high doping [4,7,19]; 2) Increasing of the 2D band position corresponds to p-doping, as predicted theoretically [4,7,15]; 3) The integrated intensity ratio I(2D)/I(G) decreases, because the doping generates an additional contribution on the electron scattering defect (increasing γ’), where the intensity of the 2D band is proportional to 1/γ’2 [15,20]
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