▎ 摘　　要

Graphene layers were synthesized using ultrasonic dispersion of graphite flakes followed by ultracentrifugation in sodium cholate and polyoxyethylene nonylphenyl ether aqueous solutions. The synthesized graphene layers were characterized using Raman spectroscopy and atomic force microscopy (AFM). Typical G-band and 2D-band Raman signatures of graphene at similar to 1590 cm(-1) and similar to 2695 cm(-1), respectively, were observed in the Raman spectra of the synthesized graphene samples. The AFM height profiles of the synthesized graphene samples on SiO2 substrates show features that can be attributed to graphenes of a single layer or a few layers.