We investigate the near-field optical coupling between a single semiconductor nanocrystal (quantum dot) and a nanometer-scale plasmonic metal resonator using rigorous electrodynamic simulations. Our calculations show that the quantum dot produces a dip in both the extinction and scattering spectra of the surface-plasmon resonator, with a particularly strong change for the scattering spectrum. A phenomenological coupled-oscillator model is used to fit the calculation results and provide physical insight, revealing the roles of Fano interference and hybridization. The results indicate that it is possible to achieve nearly complete transparency as well as enter the strong-coupling regime for a single quantum dot in the near field of a metal nanostructure.

Uniformly distributed ZnO nanorods have been grown by plasma-enhanced chemical vapor deposition using a two-step process. By controlling the oxygen content in the gas mixture during the nucleation and growth steps, no catalyst is required for the formation of ZnO nanorods. High-resolution transmission electron microscopy studies show that ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. Alignment of these nanorods with respect to the substrates depends on the lattice mismatch between ZnO and the substrate, the surface electric field, and the amount of defects in the starting nuclei. Room-temperature photoluminescence measurements of these ZnO nanorods have shown ultraviolet peaks at 380 nm with a full width at half-maximum of 106 meV, which are comparable to those found in high-quality ZnO films. Photoluminescence measurements of annealed ZnO nanorods in hydrogen and oxygen atmospheres indicate that the origins of green emission are oxygen vacancies and zinc interstitials, while oxygen interstitials are responsible for the orange-red emission. A mechanism for the nanorod growth is proposed.

Since its initial discovery just over a decade ago, blinking of semiconductor nanocrystals has typically been described in terms of probability distributions for durations of bright, or "on," states and dark, or "off," states. These distributions are obtained by binning photon counts in order to construct a time series for emission intensity and then applying a threshold to distinguish on states from off states. By examining experimental data from CdSe/ZnS core/shell nanocrystals and by simulating this data according to a simple, two-state blinking model, we find that the apparent truncated power-law distributions of on times can depend significantly on the choices of binning time and threshold. For example, increasing the binning time by a factor of 10 can double the apparent truncation time and change the apparent power-law exponent by 30%, even though the binning time is only 3% of the truncation time. Our findings indicate that stringent experimental conditions are needed to accurately determine blinking-time probability distributions. Similar considerations should apply to any phenomenon characterized by time series data that displays telegraph noise.

Improvement of silver nanoparticle impregnation on cotton fabrics using a binderMejoramiento de la absorción de nanopartículas de plata en telas de algodón, utilizando un ligante Melhoramento da absorção de nanopartículas de prata em tecidos de algodão, utilizando um ligante

No abstract