  The structural and electronic properties of fluorine (F)-doped BN nanotubes
(BNNTs) are studied using density functional methods. Our results indicate that
F atoms prefer to substitute N atoms, resulting in substantial changes of BN
layers. However, F substitutional doping results in no shallow impurity states.
The adsorption of F atoms on B sites is more stable than that on N sites. BNNTs
with adsorbed F atoms are p-type semiconductors, suggesting the electronic
conduction in F-doped multiwalled BNNTs with large conductivity observed
experimentally might be of p-type due to the adsorbed F atoms, but not n-type
as supposed before.
