Morphology and optical properties of island metal films on semiconductor surface (original) (raw)
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Thin Solid Films, 2015
The films consisting of gold nanoparticles, prepared by electron beam evaporation on glass substrates, exhibit interesting optical properties due to localized surface plasmon resonance. The tailoring of optical properties has been achieved by varying deposition mass thickness and substrate temperature. The relation between optical and structural properties has been studied. Optical characterization of samples has been carried out by variable angle spectroscopic ellipsometry and for structural characterization grazing incidence small angle X-ray scattering and atomic force microscopy have been used. Results show how the structural properties, obtained by using specific fabrication parameters, influence the resulting optical characteristics. The differences in concentration, shape and size of the produced gold nanoparticles result in a spectral shift of localized surface plasmon resonance, and a change of its width and intensity. The appearance of percolation is signed by Drude-like infrared absorption.
Optical properties of gold island films—a spectroscopic ellipsometry study
Thin Solid Films, 2011
Metal island films of noble metals are obtained by deposition on glass substrates during the first stage of evaporation process when supported metal nanoparticles are formed. These films show unique optical properties, owing to the localized surface plasmon resonance of free electrons in metal nanoparticles. In the present work we study the optical properties of gold metal island films deposited on glass substrates with different mass thicknesses at different substrate temperatures. The optical characterization is performed by spectroscopic ellipsometry at different angles of incidence and transmittance measurements at normal incidence in the same point of the sample. Fitting of the ellipsometric data allows determining the effective optical constants and thickness of the island film. A multiple oscillator approach was used to successfully represent the dispersion of the effective optical constants of the films.
2008
Metal island films show unique optical properties owing to the local surface plasmon resonance of islands free electrons. In the present study, the electric field assisted dissolution of clusters in metal island films is reported. Island films of Au, Ag, and Cu are deposited under different conditions by thermal evaporation and coated with thin dielectric layers. The samples are treated with the simultaneous application of an intense electric field and temperature, leading to the sample partial or total bleaching due to the dissolution of metal clusters in the films. Owing the facility of production of metal island films and the inexpensive technical requirements of the dissolution process, this approach suggests a novel path for the production of low-cost photonic structures.
Optical and structural properties of Au-Ag islands films for plasmonic applications
Applied Physics A-materials Science & Processing, 2011
Bimetallic islands films consisting of composite Au-Ag nanoparticles are deposited on glass substrates by electron beam evaporation. Broad tuning of the surface-plasmon resonance (SPR) characteristics can be achieved by controlling film composition, deposition temperature and post-deposition thermal annealing. Optical and structural characterization of the samples enable one to establish the link between the SPR and the morphological and compositional characteristics of nanoparticles.
Laser deposition of bimetallic island films
Journal of Physics: Conference Series, 2016
In this work the results of a bimetallic Au-Ag structure deposition from the colloidal system by nanosecond laser radiation are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. We report the results of formation bimetallic islands films with various electrical and optical properties. The changes in the optical properties of the obtained thin films are found to depend on their morphology.
The European Physical Journal B, 2011
The extinction spectrum of a dielectric film with periodic array of metallic islands of different shapes and different mutual distances was studied both theoretically and experimentally. It is shown, analytically, numerically and experimentally, that the positions of the surface plasmon resonances depend on the nano-structural details. We propose two ways of controlling plasmon resonance frequency: changing the aspect ratio of the elliptical (or rectangular) islands and changing their mutual distances. A new analytical asymptotic approach for calculating the optical properties of such plasmonic systems is developed. The results of our analytical and numerical studies are in good qualitative agreement with experiment.
Proceedings of SPIE, 2010
The extinction spectrum of a dielectric film with periodic array of metallic islands of different shapes and different mutual distances was studied both theoretically and experimentally. It is shown, analytically, numerically and experimentally, that the positions of the surface plasmon resonances depend on the nano-structural details. We propose two ways of controlling plasmon resonance frequency: changing the aspect ratio of the elliptical (or rectangular) islands and changing their mutual distances. A new analytical asymptotic approach for calculating the optical properties of such plasmonic systems is developed. The results of our analytical and numerical studies are in good qualitative agreement with experiment.
Morphology and optical properties of gold thin films prepared by filtered arc deposition
Thin Solid Films, 1999
This study report on the optical properties and scanning tunneling microscopy (STM) observations of the morphology of gold thin ®lm prepared by a ®ltered arc deposition (FAD) process. The optical properties of FAD deposited ®lms were found to be superior to those prepared with d.c. magnetron and comparable to the best reported properties in the literature. We found that Au ®lm surface roughness increased with increasing substrate bias (i.e. ion energy). Also ®lms prepared at zero substrate bias were found to be smoother to those prepared by thermal evaporation and magnetron sputtering. The smoothness of the gold ®lm, excellent optical properties and high deposition rate makes them attractive for a number of fundamental and technological applications. q 1999 Elsevier Science S.A. All rights reserved.
Optical and structural characterization of silver islands films on glass substrates
Vacuum, 2009
Metal island films (MIFs) of Ag on glass substrates were fabricated by the e-beam evaporation technique. The dependence of the surface plasmon (SP) absorption properties on the deposition mass thickness and substrate temperature was quantified. The structural and optical characterization of the MIFs, obtained using spectrometry, grazing-incidence small-angle X-ray scattering (GISAXS) and atomic force microscopy (AFM) evidences the evolution of SP characteristics depending on the fabrication parameters: the red shift of the absorption peaks with the increase of deposition thickness accompanied by peak widening and the blue-shift of peaks with the increase of deposition temperature followed by the peak narrowing. These findings were explained by the differences in the concentration, shape and size of the obtained silver islands.
Scripta Materialia, 2001
The optical properties of nanocomposite thin films of gold, silver and bimetallic silvergold clusters embedded in a porous alumina matrix have been investigated in the size range 2-6.7 nm. The metallic particles are produced by laser vaporization of either an Au 0.5 Ag 0.5 alloy or a pure metal target whereas the dielectric matrix is evaporated by an electron gun. Samples involving a low metal concentration have been characterized by several complementary techniques in order to determine their composition, morphology and cluster size distribution. The mixed particles have the same stoichiometry as the target rod. Optical absorption spectra exhibit a surface plasmon resonance whose position is shifting with cluster mean size, giving evidence of finite size effects. Theoretical calculations in the framework of Time-Dependent-Local-Density-Approximation (TDLDA), taking into account an inner skin of ineffective screening and the porosity of the matrix, are consistent with observed size evolutions of the Mie frequency in each type of sample.