Despite the attractive one-dimensional (1D) characteristics of carbon nanotubes 1 , their typically low luminescence quantum yield (QY), restricted because of their 1D nature 2-9 , has limited the performance of nanotube-based light-emitting devices 10,11. Here we report the striking brightening of excitons (bound electron-hole pairs) 12,13 in carbon nanotubes through an artificial modification of their effective dimensionality from 1D to 0D. Exciton dynamics in carbon nanotubes with luminescent, local 0D-like states generated by oxygen doping 14 were studied as model systems. We found that the luminescence QY of the excitons confined in the 0D-like states can be more than at least one order larger (~18%) than that of the intrinsic 1D excitons (typically ~1%), not only because of the reduced non-radiative decay pathways but also owing to an enhanced radiative

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We fabricated single-crystal ZnO nanowires at a low temperature of 500 °C without using any metal catalysts via the simple thermal oxidation of metallic Zn precursors. Scanning electron microscopy and high-resolution transmission electron microscopy (HRTEM) studies showed that the ZnO nanowires with orientation-selectivity grew laterally along the sides of the hexagonal-shaped ZnO matrix transformed from the metallic Zn precursors. It was found that the nanowires grew along the 〈112̄0〉 direction and were single crystals by HRTEM study. Typically, the lengths of the ZnO nanowires ranged from 0.5 to 3 μm and their mean diameter was 20±5 nm. Photoluminescence and cathodoluminescence measurements at room temperature showed a strong ultraviolet emission peak with negligibly weak green emissions, confirming that the individual ZnO nanowire was of excellent optical quality. Based on these results, we conclude that the simple thermal oxidation of metal Zn precursors is a useful, feasible approach for fabricating high-quality one-dimensional ZnO nanostructures for integration into nanophotonic integrated circuits.

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We demonstrated the deposition of nanometric Zn dots using photodissociation with gas-phase diethylzinc and an optical near field under nonresonant conditions. To explain the experimental results, we proposed an exciton-phonon polariton model, and discuss the quantitative experimental dependence of the deposition rate on the optical power and photon energy based on photodissociation involving multiple-step excitation via molecular vibration modes. The physical basis of this process, which seems to violate the Franck-Condon principle, is the optically nonadiabatic excitation of the molecular vibration mode due to the steep spatial gradient of the optical near-field energy.