General equation for the determination of the crystallite size La of nanographite by Raman spectroscopy

This work presents a systematic study of the ratio between the integrated intensities of the disorder-induced D and G Raman bands (I-D/I-G) in nanographite samples with different crystallite sizes (L-a) and using different excitation laser energies. The crystallite size L-a of the nanographite samples was obtained both by x-ray diffraction using synchrotron radiation and directly from scanning tunneling microscopy images. A general equation for the determination of L-a using any laser energy in the visible range is obtained. Moreover, it is shown that I-D/I-G is inversely proportional to the fourth power of the laser energy used in the experiment. (c) 2006 American Institute of Physics.