Electronic structure of the Fe-layer-catalyzed carbon nanotubes studied byx-ray-absorption spectroscopy

X-ray-absorption near edge structure (XANES) measurements have been perform ed to investigate the local electronic structures of the Fe-catalyzed and s tabilized carbon nanotubes (CNT) with various diameters. The intensities of the pi*- and sigma*-band and the interlayer-state features in the C K-edge XANES spectra of these CNTs vary with the diameter of the CNT. The white-l ine features at the C K- and Fe L-3-edges suggest a strong hybridization be tween the C 2p and Fe 3d orbitals, which lead to an enhancement of the C K- and reduction of the Fe L-3-edge features, respectively, indicative of a c harge transfer from C 2p to Fe 3d orbitals. The Fe K-edge spectra reveal a p-d rehybridization effect that reduces p-orbital occupation at the Fe site . (C) 2001 American Institute of Physics.