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Studying the local character of Raman features of single-walled carbon nanotubes along a bundle using TERS.

Peica N, Thomsen C, Maultzsch J - Nanoscale Res Lett (2011)

Bottom Line: Moreover, using TERS we are able to position different single-walled carbon nanotubes along a bundle, by correlating the observed radial breathing mode (RBM) with the AFM topography at the measuring point.The frequency of the G- mode behaves differently in TERS as compared to far-field Raman.Using the RBM frequency, the diameters of the tubes were calculated and a very good agreement with the G--mode frequency was observed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr, 36, 10623 Berlin, Germany. peica@physik.tu-berlin.de.

ABSTRACT
Here, we show that the Raman intensity of the G-mode in tip-enhanced Raman spectroscopy (TERS) is strongly dependent on the height of the bundle. Moreover, using TERS we are able to position different single-walled carbon nanotubes along a bundle, by correlating the observed radial breathing mode (RBM) with the AFM topography at the measuring point. The frequency of the G- mode behaves differently in TERS as compared to far-field Raman. Using the RBM frequency, the diameters of the tubes were calculated and a very good agreement with the G--mode frequency was observed.

No MeSH data available.


Related in: MedlinePlus

Left-hand side: Height profiles of the seven measured positions along an SWCNTs bundle. Right-hand side: AFM topography together with an approximation of the far-field spot area (green ellipse), diffraction-limited area (green circle), the near-field area (small blue circle), and the y-polarization direction of the incident laser. (A), (B), and (C) denote the three different bundles observed in the AFM topography. This notation is used in the RBM discussion part.
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Figure 1: Left-hand side: Height profiles of the seven measured positions along an SWCNTs bundle. Right-hand side: AFM topography together with an approximation of the far-field spot area (green ellipse), diffraction-limited area (green circle), the near-field area (small blue circle), and the y-polarization direction of the incident laser. (A), (B), and (C) denote the three different bundles observed in the AFM topography. This notation is used in the RBM discussion part.

Mentions: We performed TERS and confocal Raman measurements at seven different positions along a small SWCNTs bundle in order to study the local character of different Raman features of SWCNTs. The seven positions along the SWCNTs bundle are depicted in Figure 1 together with their corresponding AFM height profiles. Figure 1 shows the optically excited areas in the far-field (green ellipse) as well as in the near-field (blue circle). The tip-induced enhancement is coming from the small excited area in the near-field (Figure 1, blue circle) whereas the total signal in TERS always includes the confocal Raman signal, coming from the same area as in the far-field (Figure 1, green ellipse) and thus including more carbon nanostructures than the near-field area. The incident laser is coming under an angle of 60° with respect to the surface normal and its polarization direction is depicted in Figure 1 by the y-axis of the green ellipse.


Studying the local character of Raman features of single-walled carbon nanotubes along a bundle using TERS.

Peica N, Thomsen C, Maultzsch J - Nanoscale Res Lett (2011)

Left-hand side: Height profiles of the seven measured positions along an SWCNTs bundle. Right-hand side: AFM topography together with an approximation of the far-field spot area (green ellipse), diffraction-limited area (green circle), the near-field area (small blue circle), and the y-polarization direction of the incident laser. (A), (B), and (C) denote the three different bundles observed in the AFM topography. This notation is used in the RBM discussion part.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211227&req=5

Figure 1: Left-hand side: Height profiles of the seven measured positions along an SWCNTs bundle. Right-hand side: AFM topography together with an approximation of the far-field spot area (green ellipse), diffraction-limited area (green circle), the near-field area (small blue circle), and the y-polarization direction of the incident laser. (A), (B), and (C) denote the three different bundles observed in the AFM topography. This notation is used in the RBM discussion part.
Mentions: We performed TERS and confocal Raman measurements at seven different positions along a small SWCNTs bundle in order to study the local character of different Raman features of SWCNTs. The seven positions along the SWCNTs bundle are depicted in Figure 1 together with their corresponding AFM height profiles. Figure 1 shows the optically excited areas in the far-field (green ellipse) as well as in the near-field (blue circle). The tip-induced enhancement is coming from the small excited area in the near-field (Figure 1, blue circle) whereas the total signal in TERS always includes the confocal Raman signal, coming from the same area as in the far-field (Figure 1, green ellipse) and thus including more carbon nanostructures than the near-field area. The incident laser is coming under an angle of 60° with respect to the surface normal and its polarization direction is depicted in Figure 1 by the y-axis of the green ellipse.

Bottom Line: Moreover, using TERS we are able to position different single-walled carbon nanotubes along a bundle, by correlating the observed radial breathing mode (RBM) with the AFM topography at the measuring point.The frequency of the G- mode behaves differently in TERS as compared to far-field Raman.Using the RBM frequency, the diameters of the tubes were calculated and a very good agreement with the G--mode frequency was observed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr, 36, 10623 Berlin, Germany. peica@physik.tu-berlin.de.

ABSTRACT
Here, we show that the Raman intensity of the G-mode in tip-enhanced Raman spectroscopy (TERS) is strongly dependent on the height of the bundle. Moreover, using TERS we are able to position different single-walled carbon nanotubes along a bundle, by correlating the observed radial breathing mode (RBM) with the AFM topography at the measuring point. The frequency of the G- mode behaves differently in TERS as compared to far-field Raman. Using the RBM frequency, the diameters of the tubes were calculated and a very good agreement with the G--mode frequency was observed.

No MeSH data available.


Related in: MedlinePlus