Computation of the optical constants of thermally-evaporated thin films of GeSe₂chalcogenide glass from their reflection spectra

Abstract

The interference modulated reflection spectra R(λ) at normal incidence for amorphous GeSe2 semiconducting films, deposited by thermal evaporation, were obtained in the spectral region from 400 nm to 2200 nm. The straightforward method proposed by Minkov, which is based on the use of the extrema of the interference fringes R(λ), has been applied in order to obtain both the real and imaginary parts of the complex refractive index, n and k, respectively, and the film thickness, d. Thickness measurements made by a surface-profiling stylus have also been carried out to cross-check the results obtained by the optical method. The dispersion of n is discussed in terms of the single-oscillator Wemple-DiDomenico model.