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Dispersive Fourier Transform Spectroscopy Of Free-Standing Porous Silicon Films

Published online by Cambridge University Press:  10 February 2011

J. Salonen
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
K. Saarinen
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
J. Peura
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
J. Vilnikanoja
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
I. Salomaa
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
E. Laine
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
J Kauppinen
Affiliation:
Department of Physics and Department of Applied Physics, University of Turku, FIN-20014 Turku, Finland
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Abstract

We have investigated optical constants of free-standing porous silicon films by dispersive Fourier transform spectroscopy (DFTS) in the NIR-VIS range. This allows the spectral variation of both the absorption coefficient and the refractive index of a material to be determined from the measurements of the attenuation and phase shift imposed on an electromagnetic wave by its interaction with a specimen. Using these optical constants, we have studied the complex dielectric function and the complex conductivity. To avoid the additive error in the absorption spectra arising from the pseudocoherence, we measured the transmission spectra by conventional Fourier transform spectroscopy (FTS). Using the refraction spectrum derived from the DFTS measurements, we have corrected for reflection losses in calculation of the absorption spectrum from the FTS transmission spectrum. The changes in the absorption coefficient and the refractive index due to oxidation, which is the most common aging phenomenon in porous silicon, have been studied using samples with different types of oxidization.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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