Comparative high pressure Raman study of boron nitride nanotubes and hexagonal boron nitride

High pressure Raman experiments on boron nitride multi-walled nanotubes show that the intensity of the vibrational mode at similar to 1367 cm(-1) vanishes at similar to 12 GPa and it does not recover under decompression. In comparison, the high pressure Raman experiments on hexagonal boron nitride show a clear signature of a phase transition from hexagonal to wurtzite at similar to 13 GPa which is reversible on decompression. These results are contrasted with the pressure behavior of carbon nanotubes and graphite. (c) 2006 Elsevier B.V. All rights reserved.