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Nanocrystalline thin films of Sb37.07Mn1.95Se60.98 with different thickness (7, 20, 40, and 80 nm) were successfully prepared via inert gas condensation technique. As-deposited films showed amorphous structure by grazing incident in-plane X-ray diffraction (GIIXD) technique. All films of different thicknesses were heat treated at 433 K for 90 min. The GIIXD pattern of annealed films showed nanocrystalline orthorhombic structure. The effect of thickness of annealed films on the structure and optical properties was studied. Calculated particle sizes are 20.67 and 24.15 for 40 and 80 nm thickness of heat treated film. High resolution transmission electron microscope HRTEM images and their diffraction patterns proved that 40 nm film thickness annealed at different temperature has nanocrystalline nature with observed (high) crystallinity that increases with annealing temperature. Blue shift of optical energy gap was observed from 1.68 to 2 eV with decreasing film thickness from 80 to 7 nm. Film thickness of 40 nm was exposed to different heat treated temperatures from 353 to 473 K to detect its effect on structure and optical and electrical properties. Blue shift from 1.73 to 1.9 eV was observed in its optical band gap due to direct transition as heat treatment temperature decreasing from 473 to 353 K. Electrical conductivity was studied for different heat treated films of thickness 40 nm, and intrinsic conduction mechanism is dominant. The activation energy Ea was affected by heat treatment process.

Thin films of Sb 2 Te 2 Se were prepared by conventional thermal evaporation of the presynthesized material on Corning glass substrates. The chemical composition of the samples was determined by means of energydispersive X-ray spectrometry. X-ray diffraction studies on the as-deposited and annealed films revealed an amorphous-to-crystalline phase transition. The as-deposited and annealed films at T a = 323 and 373 K are amorphous, while those annealed at T a = 423 and 473 K are crystalline with a single-phase of a rhombohedral crystalline structure as that of the source material. The unit-cell lattice parameters were determined and compared with the reported data. The optical constants (n, k) of the investigated films were determined from the transmittance and reflectance data at normal incidence in the spectral range 400-2500 nm. The analysis of the absorption spectra revealed non-direct energy gaps, characterizing the amorphous films, while the crystalline films exhibited direct energy gaps.

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Rietveld Method. -The solid solutions CuxAg1-xInTe2 (x = 0.0, 0.25, 0.50, 0.75, 1.0) are synthesized by fusion of the constituent elements in stoichiometric ratios (1373 K, 24 h, sealed silica tubes). As revealed by powder XRD, the samples crystallize in the chalcopyrite type structure (space group I42d). The influence of the Cu-content on the structural properties of the bulk material is discussed. -(MOUSTAFA, A. M.; EL-SAYAD*, E. A.; SAKR, G. B.; Cryst. Res.

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