Temperature coefficients of Raman frequency of individual single-walled carbon nanotubes

In the present study, individual suspended single-walled carbon nanotubes (SWNTs) were prepared and the temperature coefficients of Raman frequency of 13 SWNTs were measured. It is found that the temperature coefficients of the G-band frequency (alpha(omega G)) are similar, around (- 1.67 +/- 0.20) x 10(-5)/K, whereas in the case of the radial breathing mode (RBM), the coefficients (alpha(omega RBM)) are varied from a minimum value of -1.06 x 10(-6)/K to a maximum of -2.30 x 10(-4)/K. Larger-diameter nanotubes tend to have larger alpha(omega RBM) values; moreover, nanotubes with similar diameters may show different alpha(omega RBM) values. These results reveal that the alpha(omega RBM) value of individual SWNTs depends on both diameter and chirality.