Carbon nanotubes: opportunities and challenges

Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The association of these properties in a single material explains the vast domain of its applicability and the diverse production methods which have emerged. Although the different properties of tin doped indium oxide in the film form are interdependent, this article mainly focuses on the electrical aspects. Detailed description of the conduction mechanism and the main parameters that control the conductivity is presented. On account of the large varieties and differences in the fabrication techniques, the electrical properties of ITO films are discussed and compared within each technique.

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Tin doped indium oxide thin films: Electrical properties

Microscopic view of epitaxial metal growth: nucleation and aggregation

Metal coating on suspended carbon nanotubes and its implication to metal–tube interaction

We studied the shape transformation (by use of TEM and optical absorption spectroscopy) of gold nanorods in micellar solution by exposure to laser pulses of different pulse width (100 fs and 7 ns) and different energies (μJ to mJ) at 800 nm, where the longitudinal surface plasmon oscillation of the nanorods absorb At moderate energies, the femtosecond irradiation melts the nanorods to near spherical particles of comparable volumes while the nanosecond pulses fragment them to smaller near-spherical particles At high energies, fragmentation is also observed for the femtosecond irradiation A mechanism involving the rate of energy deposition as compared to the rate of electron−phonon and phonon−phonon relaxation processes is proposed to determine the final fate of the laser-exposed nanorods, ie, melting or fragmentation

Laser photothermal melting and fragmentation of gold nanorods: Energy and laser pulse-width dependence

We present a quantitative study of the diffusion of spherical antimony clusters deposited on graphite surfaces. The experimental structures obtained during deposition are compared to predictions of recent computer models, and very good agreement is found. From this comparison we can obtain the diffusion coefficient of large antimony clusters containing around 2300 atoms moving on a graphite substrate: we find ${D\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}D}_{0}\mathrm{exp}({\ensuremath{-}E}_{a}/{k}_{B}T)$ with ${D}_{0}\ensuremath{\approx}1.6\ifmmode\times\else\texttimes\fi{}{10}^{4}{\mathrm{cm}}^{2}/\mathrm{s}$ and ${E}_{a}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.7\ifmmode\pm\else\textpm\fi{}0.1\mathrm{eV}$. This large value of ${D}_{0}$ suggests that the diffusion cannot be explained by a simple atomic activated process, but may rather involve collective motions of the atoms of the cluster.

Experimental observation of fast diffusion of large antimony clusters on graphite surfaces.

In this paper the specific properties of free clusters and the formation of new cluster-assembled materials using the low energy cluster beam deposition (LECBD) technique are discussed. Recent results obtained for free clusters are summarized with special attention to new observed structures. As for the specific structures and properties of cluster-assembled materials, two main aspects are specially emphasized: the memory effect of the free cluster properties leading to the formation of new phases and the effect of the specific nanostructure of the cluster-assembled materials related to the random cluster stacking mechanism characteristic of the LECBD. These effects and the corresponding potential applications are illustrated using some selected examples: new diamond-like carbon films produced by fullerene depositions (memory effect) and grain effect on the magnetic properties of cluster-assembled transition metal films.

From Free Clusters to Cluster-Assembled Materials

Diffusion and aggregation of large antimony and gold clusters deposited on graphite

Cluster-beam deposition of thin metallic antimony films: Cluster-size and deposition-rate effects.

Barium clusters are produced by the inert-gas condensation technique. The observed size distribution shows large peaks at n=13, 19, 23, 26, 29, 32, as well for singly charged clusters as for doubly and triply charged clusters. These results can be interpreted by icosahedral close-packing structures, similar to those observed in noble-gas clusters.

Alain Hoareau

Papers

Experimental observation of fast diffusion of large antimony clusters on graphite surfaces.

From Free Clusters to Cluster-Assembled Materials

Diffusion and aggregation of large antimony and gold clusters deposited on graphite

Cluster-beam deposition of thin metallic antimony films: Cluster-size and deposition-rate effects.

Close-packing structure of small barium clusters