▎ 摘　　要

We report that single-walled carbon nanotubes (SWNTs) can be etched into graphene nanoribbons (GNRs) by iron etching, which is confirmed by Raman spectroscopy and transmission electron microscopy. Compared with SWNTs, there are some unique features in Raman spectra of GNRs: symmetric G peak with no splitting, larger Raman intensity of 2D peak than G peak, and lower frequency and narrower full width at half maximum for 2D peak. Similar to radial breathing modes in SWNTs, theoretically predicted radial breathing-like mode of GNRs is also observed: a clear and prominent peak around 223 cm(-1) in the low frequency regions. This work paves the way for future studies of nanodevices based on SWNT-GNR heterojunction. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3692108]