**3. Characterization experiments for SWCNTs**

In previous work [28, 32], we found the suitable parameters for SWCNTs production:


**Figure 7.** Photograph of the new and previous designed cold fingers.

of the ablation products, i.e., the final products.

**2.3. Original target preparation method**

**Table 1.** The parameters used for carbon nanomaterial synthesis.

NLPM.

percentage).

The longer cold finger provides a larger surface resulting in a better percentage collection of the ablation products. The temperature gradient induced by the collector outside the oven area is distributed on a larger length of the cold finger, as presented in **Figure 6(b)**. This provides the means to study the influence the cold finger temperature gradient has on the condensation

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

(iii) The attached Alicat flow meter controller allows controlling accurately the flow rate of the carrier gas over a wide range, 0–10 normal liters per minute (NLPM), with a resolution of 0.01

The target was prepared by following a recipe developed by Enachescu's group [28, 31, 32]. This recipe involves the mixing of graphite cement (GC 8010-B from Metal Forming Lubricants) with metal catalysts powder (Sigma Aldrich). We have studied several target compositions using uni- as well as bi-components metal catalysts. From all the combinations the best composition for SWCNTs synthesis was found to be Co 0.6%, Ni 0.6%, and C 98.8% (atomic

The mixture was transferred into a Teflon mold (20 mm diameter) and then cured 4 h at 130°C in air to increase the mechanical strength. Further another heat treatment of the target was applied for 1 h at 800°C in inert atmosphere to remove all the remaining organic compounds.

**Material type Pressure (Torr)** *T* **(°C)** *E* **(mJ) RR (Hz) Flow L/h Catalyst**

SWCNTs 500 1100 650 30 70 yes

CNOs 7 900 700 10 300 no

Graphene 100 1100 700 30 300 no


In the next subchapters we present the characterisation of SWCNTs obtained under above described conditions.
