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The Ag-mixed Se 70 Te 30 thermally deposited semiconducting thin films show interesting thermoelectric properties. As the Ag content in the structure of Se 70 Te 30 increases, the Seebeck coefficient increases. The semiconductive thin films reveal a p-type behavior. The dark conductivity increases at 300 K, whereas a reduction in corresponding activation energy for dark, photo and thermal response is observed with the increase in the Ag content. It is elucidated that the power factor for Se 70 Te 30 100 - x Ag x (0.0 ≤ x ≤ 8.0 at. %) semiconducting thin films can be tuned and enhanced at varied temperature ranges through adjusting the addition amount of Ag. These results indicate that these semiconducting thin films have remarkable potential as thermoelectric generators. [ABSTRACT FROM AUTHOR]

We report kinetics of photodarkening of a-As2Se3 films in terms of changes in absorption coefficient and optical band gap. These are estimated by in situ measurements of transmission spectra at intervals of 10 ms under laser illumination. The absorption coefficient increase with increasing time of laser illumination before saturating. The change in optical band gap, estimated from transmission spectra are studied as a function of time and intensity. A theoretical fitting of the change in optical parameters is done using photon-assisted site switching model, yielding the time constants for the changes in optical absorption and optical band gap. The change in absorption coefficient and optical band gap with incident laser intensity is also examined to investigate the saturation phenomenon. [ABSTRACT FROM AUTHOR]

The kinetics of photodarkening of a-[As.sub.2][Se.sub.3] films in terms of changes in absorption coefficient and optical band gap are described. The change in absorption coefficient and optical band gap with incident laser intensity is examined in order to evaluate the saturation phenomenon.

Abstract: The evolution of the structure of Sb x Ge40-x Se60 (x =8, 12, 15, 18 and 20) chalcogenide glasses is determined by high resolution X-ray photoelectron spectroscopy as Sb is added and the average coordination number (Z) is varied from 2.60 to 2.72. For glasses with Z <2.67 the structure consists of deformed tetrahedra and pyramids, in which at least one Se atom is substituted by Ge or Sb atoms. Increase in the concentration of cations beyond Z ≥2.67 leads to a strengthening of the above regularity and formation of the structure by shared pyramids and tetrahedra with two or more Se atoms substituted by cations. At the same time Se–Se dimers are present in all the investigated compositions while they are not expected in these Se-deficient glasses. Their formation dictates that there must be metal-rich regions somewhere in the structure. [Copyright &y& Elsevier]