Abstract
Thin film samples of different thicknesses ranging from 167.5 to 647.4 nm, were prepared from the synthesized amorphous Se85Te15-xSbx (x = 0, 2, 4 and 6 at.wt%) chalcogenide glass compositions by thermal evaporation technique. X-ray diffraction analysis showed the amorphous nature of the obtained films. The dc electrical conductivity was studied for the prepared films as a function of temperature in range (297-333 K) below the glass transition temperature T-g. From the obtained results of sigma(dc) the conduction activation energy Delta E-sigma has a single value indicating the presence of one conduction mechanism throughout the studied range of temperature. The obtained results of sigma(dc) are explained in accordance with Mott and Davis model. The current-voltage (I-V) characteristics curves showed a memory type switch. The mean value of the threshold voltage (V) over bar (th) increases linearly with increasing film thickness and decreases exponentially with temperature for all investigated film compositions. Values of the threshold voltage activation energy (epsilon) over barV(th) were obtained for the studied films. The switching phenomenon in the investigated films is explained on the basis of the electrothermal model initiated from Joule heating of current channel. The effect of the Sb addition on the obtained results was discussed. (C) 2011 Elsevier B.V. All rights reserved.