Densely-packed alkyl monolayers similar to those previously reported by Linford et al. 1,2 are formed by the reaction of 1-alkenes with hydrogen-terminated surfaces of both Si(111) and Si(100). The thermal behavior of these monolayers in vacuum has been studied using high-resolution electron energy loss spectroscopy. Both on Si(111) and on Si(100), the monolayers are found to be stable up to about 615 K. Desorption is signaled by a decrease in the intensity of C-H modes, accompanied by the appearance of Si-H modes, which suggests that desorption occurs through β-hydride elimination reactions. Upon further annealing to 785 K, C-H and Si-H modes essentially disappear, and a peak appears at 780 cm -1 , which is attributed to a SiC vibrational mode. This behavior indicates that decomposition of the monolayers has taken place.

We developed single-crystal poly(3,4-ethylenedioxythiopene) (PEDOT) nanowires with ultrahigh conductivity using liquid-bridge-mediated nanotransfer printing with vapor phase polymerization. The single-crystal PEDOT nanowires are formed from 3,4-ethylenedioxythiophene (EDOT) monomers that are self-assembled and crystallized during vapor phase polymerization process within nanoscale channels of a mold having FeCl3 catalysts. These PEDOT nanowires, aligned according to the pattern in the mold, are then directly transferred to specific positions on a substrate to generate a nanowire array by a direct printing process. The PEDOT nanowires have closely packed single-crystalline structures with orthorhombic lattice units. The conductivity of the single-crystal PEDOT nanowires is an average of 7619 S/cm with the highest up to 8797 S/cm which remarkably exceeds literature values of PEDOT nanostructures/thin films. Such distinct conductivity enhancement of single-crystal PEDOT nanowires can be attributed to improved carrier mobility in PEDOT nanowires. To demonstrate usefulness of single-crystal PEDOT nanowires, we fabricated an organic nanowire field-effect transistor array contacting the ultrahigh conductive PEDOT nanowires as metal electrodes.

Time-resolved atomic force microscopy and contact angle measurements reveal that the self-assembly of octadecyltrichlorosilane-based monolayers on the oxidized Si(100) surface can be initiated by three distinct mechanisms: island growth at low temperatures (T < 16 °C), homogeneous growth at high temperatures (T g 40 °C), and a mixed regime at intermediate temperatures. These results support the notion of a transient Langmuir film at the substrate-solution interface: the observed growth patterns are consistent with nucleation of liquid-condensed domains coexisting with a two-dimensional gas at low temperature, or with a liquidexpanded phase at intermediate temperatures.

Self-assembled monolayers of alkanethiols have been formed on oxidized surfaces of polycrystalline copper. For comparison, the monolayers were formed on clean copper surfaces. X-ray photoelectron spectroscopy (XPS), contact angle analysis, ellipsometry, and gas chromatography-mass spectrometry (GC-MS) have been employed to investigate the structure, formation, and thermal behavior of these monolayers. The results indicate that the structures of the monolayers on both surfaces are similar in quality, despite the fact that the oxidized copper surfaces were covered with the oxide layers of ∼500 Å thickness before monolayer formation. However, the monolayers on the oxidized copper are less stable than those on the clean copper against thermal heating in air. The observation is discussed in terms of the desorption mechanism of the monolayers. XPS and GC-MS analyses for the monolayer formation on the oxidized copper surface show that thiols are actually changed to disulfides with reduction of the oxide layers.

trolled using a closed-cycle Helium cryostat (Cryogenic Technology Inc., model 501A).Theoretical Methodology: The geometry of all compounds was fully optimized with the semiempirical PM3 (Parametric Method 3) Hamiltonian [26], which yields a coplanar structure. The vibrational frequencies were also computed at this level of theory and confirm the global minimum of the equilibrium geometry by the absence of negative frequencies. The geometric relaxation taking place in the lowest excited state has been described by coupling the PM3 method to a full CI (configuration interaction) expansion involving a limited number of orbitals (as implemented in the AMPAC package) [27]. The size of the CI active space is chosen in order to ensure the convergence of the geometric parameters. On the basis of the PM3-optimized structures, the transition energy and transition dipole moment associated to the lowest excited state of the compounds have been estimated with the help of the spectroscopic version of the semiempirical These efforts span not only layer-structured materials, but also metallic, semiconducting, and even strongly ionic bonded oxide materials. The latter, however, have often been found as nanosized tubular materials. Nanotubes and/or nanotubular oxide (and, in particular, functional oxide) materials that have particularly promising physical properties and potential applications in nanoelectronics, however, are rarely found or synthesized. Nanotubes of SiO 2 , TiO 2 , and vanadium oxides have been synthesized, using several different processing techniques. Among these, nanotubes of TiO 2 have been the most intensively investigated, since their superior catalytic properties are combined with nanotubular forms of high surface area. Much effort has been devoted to forming TiO 2 nanotubes, and nanotubular COMMUNICATIONS