- Conference date: 8-15 March 2003
- Location: Kirchberg, Tirol (AUSTRIA)
Using x‐ray induced photoelectron spectroscopy (XPS) we compare the purification of Single‐Walled Carbon Nanotubes (SWCNTs) through oxidizing treatments, namely either nitric acid (HNO3) or a combined oxidation in air / hydrochloric acid (HCl)‐etch. We find that in the raw material the catalyst metals are covered by amorphous carbon and are exposed by oxidation in air. The catalyst metals are then removed by the HCl etch. After the HNO3‐treatment no catalyst metals are observed, indicating that amorphous carbon and catalyst metals are removed in a one step process. Both acid treatments lead to p‐type doped material. In both cases p‐doping doping is removed by mild annealing (≈ 330°C). For the nitric acid treatment part of the sample is doped n‐type, which is stable upon annealing.
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