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In this work, double plasmon resonances in hybrid structures comprising Ag nanoparticles (NPs) and amorphous hydrogenated carbon films (a-C:H) have been studied. Granulated silver films with a gravimetric thickness of 10 nm were thermally deposited on top or underneath a-C:H films fabricated by plasma-assisted chemical vapour deposition on a quartz substrate. Two plasmon bands with comparable intensities have been observed in the hybrid structures optical density spectrum after annealing at 200°C. On the other hand, in the absence of the amorphous hydrogenated carbon film the short-wavelength peak in the optical density spectrum of the same Ag film is hardly observable. In addition, plasmon-enhanced photoluminescence of the a-C:H film being excited close to the spectral dip at the wavelength of 405 nm was observed. The nature of double plasmon resonance spectra were discussed and explained by the resonance interaction of plasmons excited in Ag NPs with excitons in a-C:H. [ABSTRACT FROM AUTHOR]

Quantum dots of indium gallium arsenide buried in a thin layer of aluminum gallium arsenide were grown by means of molecular-beam epitaxy. The influence of silver nanoparticles grown on the surface of the semiconductor structure by vacuum thermal evaporation on photoluminescence of quantum dots was investigated. Photoluminescence spectra of quantum dots were obtained under stationary and pulsed excitation. The influence of silver nanoparticles exhibiting plasmon resonances on spectral distribution and kinetics of luminescence of the epitaxial quantum dots was studied. [ABSTRACT FROM AUTHOR]

We propose methods for creating spherical gold particles of submicron size and silver rod-like particles with transverse dimensions of ~10 nm and an aspect ratio of 1: 10. Factors determining the frequency of plasmon resonances are considered, reagents are selected, and their ratios for obtaining prolate silver particles are determined. An optimal concentration of the surfactant is determined for creating most elongated silver particles. A shift of the plasmon absorption toward the near-IR range of the spectrum is obtained. [ABSTRACT FROM AUTHOR]

A method of formation of a composite structure based on silver nanoparticles and a thin protective silicon film (AgNPs/Si) is developed. Enhancement of the fluorescence and Raman scattering in cyaninedye molecules deposited onto the formed nanostructure is observed. The optical properties and morphology stability of particles that are in contact with cyanine-dye solutions in organic solvents are studied. It is shown that the AgNPs/Si composite structure can be multiply used as an SERS-active surface. [ABSTRACT FROM AUTHOR]

The dephasing time of localized surface plasmons is a crucial parameter that defines the quality of resonance and achievable electromagnetic field enhancement near metal nanoparticles. Lattice irregularities of as‐deposited supported metal nanoparticles shorten the plasmon dephasing time and degrade the resonance quality. To study the crystallinity influence on the plasmon dephasing time in more detail, silver nanoparticles in the form of a granular film were produced on dielectric substrates via physical vapor deposition in a vacuum chamber. The samples are characterized using Vis–NIR spectroscopy and transmission electron microscopy. The persistent spectral hole burning technique is applied to study the annealing influence on the dephasing time of localized surface plasmons of the particular resonance frequency. After annealing, the improved crystallinity of nanoparticles leads to a twofold dephasing time increase. This conclusion is supported by the electron diffraction patterns. The role of the improved crystallinity among concurrent effects of annealing is discussed. [ABSTRACT FROM AUTHOR]

The optical properties of multilayer bimetallic films composed of silver and gold nanoparticles have been investigated. The dependence of the transmission spectra of the films on their morphology is demonstrated. A finite-difference time-domain (FDTD) simulation has confirmed that there is a dependence of the transmission spectra on the average distance between particles and the number of deposited layers. [ABSTRACT FROM AUTHOR]

The formation kinetics of an island silver film on a dielectric substrate and changes in the film morphology during heating have been investigated using optical methods. The results obtained are interpreted within a model relating the film optical properties with the shape and size of the nanoparticles forming this film. The proposed interpretation is confirmed by electron microscopy data. [ABSTRACT FROM AUTHOR]

We experimentally investigate the influence of the near field of silver nanoparticles on the optical and photophysical properties of semiconductor CdSe/ZnS quantum dots. The samples are grown via deposition of metal onto dielectric substrates in a high vacuum chamber and are covered by a layer of quantum dots by means of centrifugation. We show that there is an increase in the quantum dot absorption in the near field of silver nanoparticles upon excitation in the plasmon band domain. [ABSTRACT FROM AUTHOR]

We have studied the conductivity and photoconductivity in silver nanoparticle ensembles on quartz glass substrates. We observed a significant increase of the photoconductivity if the localized surface plasmon resonance in the metal nanoparticles was excited. A detailed analysis of the temperature dependence of the conductivity as well as dependences of the conductivity and photoconductivity on the amount of deposited metal led to the mechanism of the charge transfer in these structures. We found that the primary role in this mechanism is due to defects in the quartz glass structure which act as traps for electrons. [ABSTRACT FROM AUTHOR]

Extinction spectra of a hybrid material comprised of molecular layers of polymethine dyes and granulated silver films preliminarily deposited onto sapphire substrates are studied experimentally. Specific features of the dye layer composition and broadening of plasmon absorption bands are discussed. In hybrid samples, both an increase and a decrease in the silver-nanoparticle plasmon resonance frequency upon spreading of dyes have been observed, as well as a considerable increase in the dye molecule absorption. Possible mechanisms of the phenomena are discussed. [ABSTRACT FROM AUTHOR]