Carbon nanotubes have been studied by researchers and experiments have shown a strong interaction between tubes and substrate inducing important deformation of the nanotube on top of substrate [1, 2]. In this work, carbon nanotubes were grown by catalytic chemical vapor deposition (CVD) on quartz substrate [3]. Nanotube epitaxy combined with gas flow directed leads to the formation of serpentines, i.e. SWNTs with parallel straight segments connected by alternating U-turns [3-6]. We employed confocal Raman spectroscopy with atomic force microscope (AFM) setup to study single wall carbon nanotubes (SWNTs) serpentines deposited on quartz. SWNT was pulled with a tip. The manipulation was performed dragging the SWNTs serpentines at xy-direction on the substrate and structural modifications were observed. The Raman spectrum change along the SWNT when manipulated with a gold tip. We observed a modification in the G-band frequency along the tube and not only in a specific point where dragged the tube. Under uniaxial stretch, only a downshift is observed for certain G modes due to the elongation of C-C bonds in the axial direction [7]. These results can be attributed to an interaction between the SWNT and substrate. When we drag the tube in a specific place, we change this interaction along the carbon nanotube, but the tube moves just at the point where it was pulled. This confirms the strong electronic interaction between the carbon nanotubes and the quartz surface.

Acknowledgments:

J.S.S., N.M.B.N. and A.J. acknowledge financial support from CNPq, CAPES and FAPEMIG. E.J. acknowledges support from the Israel Science Foundation, the US-Israel Binational Science Foundation, the Kimmel Center for Nanoscale Science, and the Legrain, Djanogly, Alhadeff and Perlman Family foundations.

References:

1. J. S. Soares et al. Nano Lett. 10, 5043 (2010).

2. M. Steiner et al. Appl. Phys. A 96, 271 (2009).

3. N. Geblinger et al. Nature Nanotech. 3, 195 (2008).

4. S. Jeon et al. Nano Res. 1, 427 (2008).

5. J. Huang et al. Nanotechnology 19, 505601 (2008).

J. Xiao et al. Nano Lett. 9, 4311 (2009).

7. X. Duan et al. Nano Lett. 7, 2116 (2007).

Jaqueline Soares

Universidade Federal de Ouro Preto, Universidade Federal de Minas Gerais

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