**3.3. SEM experiments**

In **Figure 10** is a collection of images obtained by a field emission scanning electron microscopy (SEM) for synthesized SWCNTs. The high resolution of SEM system of 0.6 nm, is making possible direct visualization and direct measuring of the SWCNTs bundles into SEM images. Usually such measurements are performed in high resolution transmission electron microscopy (HR-TEM), where the sample preparation is laboriously comparing with SEM sample investigations. We can identify well defined nanotubes shapes with μm length and nm diameters and observe their abundance. It is very interesting to observe their parallel arrangement.

High-Quality Carbon Nanomaterials Synthesized by Excimer Laser Ablation http://dx.doi.org/10.5772/65309 297

**Figure 9.** AFM images (a) 2D; (b) 3D; (c) 100% polymer; (d) 12% SWCNTs in polymer.

The G band in the Raman spectra clearly demonstrates, depending on the ratio of *I*G+/*I*G− that semiconducting SWCNTs were obtained, **Figure 8** (top right). However by using red excitation laser we obtain evidence of metallic SWCNTs existence (not shown here). So we conclude that

our material is a mixture of semiconducting and metallic nanotubes.

296 Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification

**Figure 8.** Micro-Raman spectra of SWCNTs – blue: our product, black: commercial product.

SWCNTs content into polymer (not shown here).

Atomic force microscopy (AFM) was involved for the synthesized SWCNTs characterization as well as for SWCNTs mixed with poly(3-octylthiophene) (P3OT) polymer, for solar cell

In **Figure 9** we present AFM images for a synthesized SWCNTs bundle on Si substrate: (a) 2D and; (b) 3D. In (c) is presented the topography of P3OT polymer on glass and (d) is 12% SWCNTs composite in P3OT polymer on glass and we can observe the SWCNTs bundles. We investigated also the adhesions forces on both surface and they increase with the increase of

In **Figure 10** is a collection of images obtained by a field emission scanning electron microscopy (SEM) for synthesized SWCNTs. The high resolution of SEM system of 0.6 nm, is making possible direct visualization and direct measuring of the SWCNTs bundles into SEM images. Usually such measurements are performed in high resolution transmission electron microscopy (HR-TEM), where the sample preparation is laboriously comparing with SEM sample investigations. We can identify well defined nanotubes shapes with μm length and nm diameters and observe their abundance. It is very interesting to observe their parallel arrange-

**3.2. AFM experiments**

**3.3. SEM experiments**

applications.

ment.

**Figure 10.** SEM images of synthesized SWCNTs.
