【研究成果】2013年

研究成果63

Tip-enhanced nano-Raman analytical imaging of locally induced strain distribution in carbon nanotubes
Taka-aki Yano, Taro Ichimura, Shota Kuwahara, Fekhra H’Dhili, Kazumasa Uetsuki, Yoshito Okuno, Prabhat Verma & Satoshi Kawata
Nature Communications 4, Article number: 2592

Tip-enhanced Raman scattering microscopy is a powerful technique for analysing nanomaterials at high spatial resolution far beyond the diffraction limit of light. However, imaging of intrinsic properties of materials such as individual molecules or local structures has not yet been achieved even with a tip-enhanced Raman scattering microscope. Here we demonstrate colourcoded tip-enhanced Raman scattering imaging of strain distribution along the length of a carbon nanotube. The strain is induced by dragging the nanotube with an atomic force microscope tip. A silver-coated nanotip is employed to enhance and detect Raman scattering from specific locations of the nanotube directly under the tip apex, representing deformation of its molecular alignment because of the existence of local strain. Our technique remarkably provides an insight into localized variations of structural properties in nanomaterials, which could prove useful for a variety of applications of carbon nanotubes and other nanomaterials as functional devices and materials.

(a) Two-dimensional colour image of a nanotube manipulated into the shape of the word ‘CNT’. This image was constructed by colour coding the frequency position of G+-mode in TERS spectra. The colour variation shows strain distribution along the nanotube at high spatial resolution. For comparison, TERS images of the same sample were constructed from (b) the intensity of G+-mode and (c) simultaneously obtained AFM topography.