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As-Se-Cu glasses, with Cu content varying between 5 and 25 at. %, were produced by quenching from the melt. The values of resistivity and activation energy for conduction decreased continuously with increasing the copper content. Memory switching phenomena was observed in glasses containing Cu less than 20 at. %. Glasses containing higher Cu concentration showed a reverse switching cycle. Thermally induced changes in the structural properties have been examined using x-ray diffraction, differential thermal analysis, and scanning electron microscopy. The results were discussed on the basis of thermally induced transformations.

In order to calculate the optical properties of evaporated Ge 30 Se 70 thin films and their relation to thickness, amorphous Ge 30 Se 70 thin films of different thicknesses were deposited by thermal evaporation at a base pressure of 7.5 × 10 −6 Torr at room temperature. The optical transmission and reflection spectra of all films were measured in the wavelength range of 0.2-2.5 m. Efficient parameterization of the spectral dependence of the optical constants of amorphous Ge-Se thin films was obtained by applying a suitable dielectric function model. The O'Leary, Johnson and Lim (OJL) model, based on joint density of states functions, was used to analyze the optical spectra. The best fit was obtained by configuring the film as two layers, the top layer consisting of bulk Ge 30 Se 70 material embedded in air medium containing different volumes of voids. Therefore, the OJL model coupled with the Bruggeman effective-medium approximation model were used to determine the optical constants of the Ge 30 Se 70 thin films. The photon energy dependence of the dielectric function, ε = ε r − iε i of the investigated films is presented. The film thickness, absorption coefficient α, refractive index n, extinction coefficient k, static refractive index n(0) and optical band gap Eg were deduced. We found that increasing the film thickness increased the direct optical energy gap and decreased the refractive index.