Strain-induced D band observed in carbon nanotubes
SWCNTs, Raman, D band, defects, strain, sp2 bond
ABSTRACT We report the emergence of the D band Raman mode in single-walled carbon nanotubes under large axial strain. The D to G mode Raman intensity ratio (ID/IG) is observed to increase with strain quadratically by more than a factor of 100-fold. Up to 5% strain, all changes in the Raman spectra are reversible. The emergence of the D band, instead, arises from the reversible and elastic symmetry-lowering of the sp2 bonds structure. Beyond 5%, we observe irreversible changes in the Raman spectra due to slippage of the nanotube from the underlying substrate, however, the D band intensity resumes its original pre-strain intensity, indicating that no permanent defects are formed.
Tsinghua University Press
Chia-Chi Chang,Chun-Chung Chen,Wei-Hsuan Hung,I. -Kai Hsu,Marcos A. Pimenta,Stephen B. Cronin, Strain-induced D band observed in carbon nanotubes. NanoRes.2012, 5(12): 854–862