Optical properties of thin GeSe2-CdI2(Sb2Se3)-CdSe films

Summary form only given. Some optical properties of thin films in the complicated chalcogenide GeSe₂-CdI₂(Sb₂ Se₃)-CdSe systems are studied as a function of the Cd and Sb content, respectively. The optical spectra of these thin films with different thickness were investigated using a spectrophotometer for the visible and IR regions. The spectra were analysed using special computer software "Layers". The investigations of the spectra of the films are carried out in the range 400-3000 nm. The general optical constants have been determined - the real and imaginary part of the dielectric function, the refractive index and the extinction. The spectral contribution of the absorption coefficient α is determined after fitting of the experimental data of R and T with simulated spectra using Lorentz-theory and Brend equations. The optical band-gap is determined by means of Tauc\´s procedure. There is evidence of structural changes in the films due to the increase of the valence density of the current carriers. The thin film structures were studied with a transmission electron microscope TEM Philips 3003. The electron microscope investigation provides information about the morphology of the films. The film composition has been investigated by Auger electron spectroscopy. The thin films, prepared under the above conditions are amorphous and without three-dimensional defects