Synthesis, Structure, and Superconducting Properties of NbC Nanorods and Nanoparticles

NbC nanorods and nanoparticles have been synthesized using a vapor-solid reaction path starting with carbon nanotube precursors. Their structures are studied using XRD, TEM, and HRSEM. Their superconducting properties of nanoparticles were also characterized using a SQUID magnetometer. For reactions at lower temperatures, NbC nanorods (10∼20 nm) which replicate the precursor carbon nanotubes are observed. For reactions at higher temperature, coarsened NbC nanoparticles (100∼500 nm) are observed which have spherical or faceted morphologies. A morphological Rayleigh instability can be applied as initiating the transition from NbC nanorod to nanoparticle morphologies. NbC nanoparticles with a little larger lattice parameter show a higher Tc than stoichiometric bulk NbC.