Energy and Charge Transfer at the Boron Nitride NanotubeCatalyst Growth Interface

For carbon nanotubes
(CNTs), the nature of the interface between the catalyst and the growing
CNT edge determines how these nanomaterials grow during chemical vapor
deposition. However, while boron nitride nanotubes (BNNTs) also require
a catalyst to grow, the nature of the BNNT–catalyst growth
interface has not been studied. Here, we characterize the BNNT–catalyst
growth interface for a wide range of potential catalysts. The primary
factor that determines the interaction between a BNNT and its catalyst
nanoparticle is interfacial charge transfer. The most stable BNNT
interface, and hence the growth mechanism itself, can be tuned by
the catalyst. In most cases, however, the zigzag BNNT edge is shown
to be preferred. We also provide evidence for the existence of growth
modes during BNNT growth, akin to those observed during CNT growth,
and recommend new growth catalysts for future experimental investigations.