Accepted Friday Oct 02, 2009
Carbon nanotubes take undoubtedly a leading position in the nanotechnology research due to their well known outstanding structural and electronic properties. Inspired on this, hybrid and functionalized tubular structures have been thought via several modification paths that involve the presence of molecules, generation of defects and partial or full replacement of the carbon atoms but always maintaining a nanotube structure. The possibilities are countless. However, this review is mainly dedicated to give a fundamental insight on the concepts behind the wall modification, doping, and general formation of single-walled nanotubes that involve the presence of boron and nitrogen as heteroatoms of the carbon nanotube structure. We cover the theoretical concepts and experimental achievements from carbon nanotubes with low B or N doping to the new physics behind boron nitride nanotubes. Furthermore, we have devoted special attention to review the bulk and local characterization tools employed with these materials, their suitability and limitations. The theoretical approaches regarding the physical and chemical properties are objectively analyzed versus the materials available at this moment.