On the bonding environment of phosphorus in purified doped single-walled   carbon nanotubes
  In this work, phosphorous-doped single-walled carbon nanotubes have been synthesized by the thermal decomposition of trimethylphosphine using a high-vacuum chemical vapor deposition method. Furthermore, a modified density-gradient-ultracentrifugation process has been applied to carefully purify our doped material. The combined use of Raman and X-ray photoelectron spectroscopy allowed us to provide the first insight into the bonding environment of P incorporated into the carbon lattice, avoiding competing signals arising from synthesis byproducts. This study represents the first step toward the identification of the bonding configuration of P atoms when direct substitution takes place. 
Georgina Ruiz-Soria, Toma Susi, Markus Sauer, Kazuhiro Yanagi, Thomas   Pichler, Paola Ayala
cond-mat.mtrl-sci