Spectral density analysis of the optical properties of Ni-Al 2O 3 nano-composite films
2011 (English)In: Advances in Optical Thin Films IV, September 5 2011, Marseille, France / [ed] Michel Lequime, H. Angus Macleod, Detlev Ristau, 2011, Vol. 8168, 81680S-1-81680S-11 p.Conference paper (Refereed)
Thin films consisting of transition metal nanoparticles in an insulating oxide exhibit a high solar absorptance together with a low thermal emittance and are used as coatings on solar collector panels. In order to optimise the nanocomposites for this application a more detailed understanding of their optical properties is needed. Here we use a highly efficient recently developed numerical method to extract the spectral density function of nickel-aluminum oxide (Ni-Al 2O 3) composites from experimental data on the dielectric permittivity in the visible and near-infrared wavelength ranges. Thin layers of Ni-Al 2O 3 were produced by a sol-gel technique. Reflectance and transmittance spectra were measured by spectrophotometry in the wavelength range 300 to 2500 nm for films with thicknesses in the range 50 to 100 nm. Transmission electron microscopy showed crystalline Ni particles with sizes in the 3 to 10 nm range. The spectral density function shows a multi-peak structure with three or four peaks clearly visible. The peak positions are influenced by particle shape, local volume fraction distributions and particle-particle interactions giving rise to structural resonances in the response of the composite to an electromagnetic field.
Place, publisher, year, edition, pages
2011. Vol. 8168, 81680S-1-81680S-11 p.
, Proceedings of SPIE, ISSN 0277-786X ; 8168
nanocomposite, thin films, optical constants, spectral density, structural resonances, sol-gel deposition
Condensed Matter Physics Engineering and Technology
Research subject Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-164014DOI: 10.1117/12.898174ISI: 000297790800023OAI: oai:DiVA.org:uu-164014DiVA: diva2:465953
Advances in Optical Thin Films IV, September 5 2011, Marseille, France
Copyright 2011 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.2011-12-152011-12-152015-06-24Bibliographically approved