Resonance Raman scattering of Br-2 doped single-walled carbon nanotube bundles

We have measured Raman spectra of bromine doped single-walled carbon nanotu bes (SWNTs) using various laser lines to clarify the electronic states of t he doped SWNT. In the case of evacuated sample after full doping, two breat hing mode peaks were observed simultaneously by visible laser excitations. We assigned the higher frequency peak to the doped SWNT bundles, and the ot her peak to the undoped portions in the sample. Intensity ratio between the m decreased with decreasing excitation energy, and in the infrared region, the breathing mode band of the doped bundle was not observed. These results can be explained by a simple rigid band model.