Abstract
We directly observed the Joule-heating-induced decomposition of multiwalled BN nanotubes using a transmission electron microscope equipped with a scanning tunneling microscope unit. The decomposition temperature is found to be dependent on an applied electrical field. We propose a model that due to the partially ionic nature of the B-N bond, the decomposition energy is both temperature- and electrical field-related: it is named as electrical field-assisted thermal decomposition. The model fits the experimental data very well and is considered to be general for all nanostructures with polar bonds. (C) 2009 Elsevier B.V. All rights reserved.