Devitrification behavior and some electrical properties of GeSeTl chalcogenide glass

The activation energy of crystallization E-c of GeSe3Tl0.3 and GeSe4Tl0.3 chalcogenide glasses was calculated from the shift of the DTA exothermic peaks with changing the heating rate. Values of E-c were calculated by different methods and it was found that it decreases with increasing Se content. Amorphous thin films of the present glasses were prepared using thermal evaporation technique. Electrical conductivity and I-V characteristics have been studied at temperatures below the glass transition temperature T-g and over a wide range of thickness (57.4-680 nm). The dc conductivity was linear in the Arrhenius Plot in the considered temperature range and increases with the increase of Se content. The activation energy for the dc conduction Delta E-sigma is decreased with increasing Se content and film thickness. The observed compositional dependence of Delta E-sigma has been correlated with the increase of weak Se-Se bond density at the expense of strong Ge-Se bond density. I-V characteristic curves indicates the memory type switching phenomenon for these compositions and it is explained in accordance with the electrothermal model initiated from Joule heating of a current channel. (C) 2010 Elsevier B.V. All rights reserved.