We have measured electrical transport properties of boron nitride nanotubes using an in situ manipulation stage inside a transmission electron microscope. Stable currents were measured in a field emission geometry, but in contact the nanotubes are insulating at low bias. At high bias, the nanotubes show stable, reversible breakdown current. q 2003 Published by Elsevier Ltd.

The threefold symmetry of planar boron nitride (BN), the III-V analog to graphene, prohibits an electric polarization in its ground state, but this symmetry is broken when the sheet is wrapped to form a BN nanotube. We show that this leads to an electric polarization along the nanotube axis which is controlled by the quantum mechanical boundary conditions on its electronic states around the tub...

The effect of divacancies on the stability, structural and electronic properties of carbon and boron nitride nanotubes is studied using the ab initio density functional method. V(B)B(N) is more stable in the boron-rich and less stable in the nitrogen-rich growth conditions, and V(N)N(B) is more stable in the nitrogen-rich than in the boron-rich conditions. We find that stoichiometric defects V(...

We calculate the tensile and shear moduli of a series of boron nitride nanotubes and their piezoelectric response to applied loads. We compare in detail results from a simple molecular mechanics (MM) potential, the universal force field, with those from the atomistic finite element method (AFEM) using both Euler-Bernoulli and Timoshenko beam formulations. The MM energy minimisations are much mo...

We demonstrate that boron nitride (BN) nanotubes can be filled "peapod" fashion with C60 molecules. Filling small-diameter BN nanotubes results in a linear chain of C60 molecules in the interior, while filling large diameter BN nanotubes leads to nanorods of crystalline C60 in the interior. Electron beam damage can be used to fuse the encapsulated C60 molecules into carbon nanotubes, leading to...

Lightweight porous ceramic materials that can recover their shapes after mechanical deformation have numerous applications. However, these types of materials tend to be highly fragile and often crack when compressed. Here, we report on the fabrication and characterization of highly porous, freestanding composites of hexagonal boron nitride (h-BN) and single-walled carbon nanotubes (SWCNTs) of d...

In recent years a significant interest has been devoted to boron nitride nanotubes (BNNTs) due to their intriguing physical properties, which make them a possible alternative to their carbon brethren in regards to possible applications [1,2,3]. However, in contrast to CNTs for which many studies have been focused in their properties, including the mechanical ones, there are almost no data for B...

We have synthesized boron nitride nanotubes (BNNTs) in an arc in presence of boron and nitrogen species only, without transition metals. We find that BNNTs are often attached to pure boron nanoparticles, suggesting that root-growth is a likely mechanism for their formation. To gain further insight into this process we have studied key mechanisms for root growth of BNNTs on the surface of a liqu...