Search

The relationship between the field emission and the density of states (DOS) of single-walled carbon nanotubes (SWCNTs) synthesized by hydrogen arc-discharge method is investigated. The results have shown that the field emission of SWCNTs can be closely related to the DOS of SWCNTs near the Fermi level.

Abstract: Composite FeO x nanoparticles embedded in carbon were prepared by the chemical vapor deposition of CH4 on iron phthalocyanine. They showed relatively high catalytic activity towards oxygen reduction, demonstrating their potential applicability as inexpensive platinum-free cathode catalysts for use in low-temperature fuel cells. Fe oxides and Fe metal embedded in porous carbon, not nitrogen-coordinated iron compounds, were shown to be the active catalytic sites in composite FeO x nanoparticles embedded in carbon. [Copyright &y& Elsevier]

Abstract: High-purity ZnO nanowires have been synthesized on Si substrates without the presence of a catalyst at 600°C by a simple thermal vapor technique. Photoluminescence (PL) spectra of the annealed samples at 900°C under oxygen and argon gases have been investigated. After O2 or Ar annealing, the PL visible-emission intensity that is related to intrinsic defects (oxygen vacancies) is greatly reduced compared with as-grown ZnO nanowires because the oxygen-gas ions or oxygen interstitials diffuse into the oxygen vacancies during annealing process. The blue-band peak of the O2- or Ar-annealed ZnO naonowires is also smaller than the green-band peak in the visible broadband because of the reduction of oxygen vacancies. Therefore, the main intrinsic defects (oxygen vacancies) of as-grown ZnO nanowires can be reduced by O2 or Ar annealing, which is an important procedure for the development of advanced optoelectronic ZnO nanowire devices. [Copyright &y& Elsevier]

Abstract: Sodium (Na)-doped C60 thin films were grown by using a high vacuum evaporation system. Ultraviolet photoelectron spectroscopy showed that the electronic density of states (DOS) of Na-doped C60 films is higher than that of undoped C60 films at 0–0.1 eV and 0.7–13.7 eV binding energy. We consider that the high electronic DOS near Fermi energy due to the Na-dopants contributes to the n-type semiconductor properties with electrical resistance of 1.5×105 Ω. We also observed that the electronic DOS of the C60 films/Cu substrate near Fermi level is higher than that of the C60 films/Si substrate indicating charge transfer at the interface. [Copyright &y& Elsevier]