M. Hrdlicka

Optically and thermally induced changes of structure, linear and non-linear optical properties of chalcogenides thin films

Abstract The spectral dependence of third-order non-linear susceptibilities, χ (3) , of amorphous As–S thin films was evaluated from changes of index of refraction using Miller’s rule. The exposure of thin fresh evaporated films and their annealing increases χ (3) , it increases also their homogeneity and level of their polymerization as can be judged from Raman spectra of the films. The large covalently bonded parts (‘molecules’) of the samples are apparently favorable for increase of χ (3) .

Ag-Sb-S Thin Films Prepared by RF Magnetron Sputtering and Their Properties

One of the recent applications of thin chalcogenide films is rewritable optical data recording. This technology is based on reversible phase transition between crystalline and amorphous state and vice versa. Dominant materials for rewritable optical recording are Ge Sb Te and Ag In Sb Te alloys. Material research still continues due to need of increasing storage capacity and data rates. Thin Ag Sb S films were prepared by RF magnetron sputtering as potential candidates for rewritable optical data storage films. There were prepared polycrystalline bulks of AgSbS 2 . Composition and homogeneity of these bulks were checked by scanning electron microscopy with energy dispersive analysis (SEM EDX) structure and bonding relations were studied by Raman spectroscopy and × ray diffraction (XRD). Targets for RF magnetron sputtering were prepared from pulverized bulks by hot pressing technique. Targets were characterized the same way as bulks. Composition and homogeneity of prepared thin films were characterized by SEM EDX, character (amorphous/crystalline) was studied by XRD. Optical properties (spectral dependence of refractive index) were evaluated on basis of UV Vis NIR spectroscopy and variable angle spectral ellipsometry (VASE). Crystallization abilities were traced by thermal dependence of optical transmission of prepared thin films.