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Multifunctional single crystalline tin-doped indium oxide (ITO) nanowires with tuned Sn doping levels are synthesized via a vapor transport method. The Sn concentration in the nanowires can reach 6.4 at.% at a synthesis temperature of 840 °C, significantly exceeding the Sn solubility in ITO bulks grown at comparable temperatures, which we attribute to the unique feature of the vapor-liquid-solid growth. As a promising transparent conducting oxide nanomaterial, layers of these ITO nanowires exhibit a sheet resistance as low as 6.4 Ω/[Symbol: see text] and measurements on individual nanowires give a resistivity of 2.4 × 10(-4) Ω cm with an electron density up to 2.6 × 10(20) cm(-3), while the optical transmittance in the visible regime can reach ∼ 80%. Under the ultraviolet excitation the ITO nanowire samples emit blue light, which can be ascribed to transitions related to defect levels. Furthermore, a room temperature ultraviolet light emission is observed in these ITO nanowires for the first time, and the exciton-related radiative process is identified by using temperature-dependent photoluminescence measurements.

Carbon nanotubes (CNTs)−magnetite nanocomposite with 20−30-nm magnetite particles attached onto CNTs has been successfully prepared for the first time by in situ solvothermal synthesis from the precursor of Fe−urea coordination complex (Fe[(NH2)2CO]6(NO3)3) and CNTs. The effects of CNTs and various processing parameters on ultimate composites characteristics were investigated. It has been found that pure CNTs−magnetite nanocomposite was obtained in an ethylenediamine medium at 200 °C for 50 h with the weight ratio of Fe[(NH2)2CO]6(NO3)3:CNTs = 10:1. XRD, BET, TEM, EDS, and a Mössbauer spectrum were used to characterize the final product. A possible formation mechanism of the CNTs−magnetite nanocomposite was suggested. It has been concluded that a suitable amount of water introduced by CNTs is critical for preparing CNTs−magnetite nanocomposite. The addition of CNTs in the composite increased the electrical conductivity by about 32% from 1.9 to 2.5 S cm-1, compared with the composite without CNTs. The relative density measurement and microstructure characterization performed by SEM showed that the percolation effect of CNTs and a good dispersion of CNTs in the matrix would lead to an effective and obvious improvement on the electrical conductivity.

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