Electrical switching behaviour of bulk As-Te-Si glasses

The current-voltage characteristics and electrical switching behavior of bulk As40Te60-xSix,, have been investigated over a wide range of compositions (2 less than or equal to x less than or equal to 14). Most of the glasses have been found to exhibit a current controlled negative resistance behavior and memory switching. The overall features of the I-V characteristics of As40Te60-xSix are not altered with the sample thickness. However, the switching voltage V-t is found to increase linearly with increasing sample thickness in the range of 0.15 mm to 0.45 mm. It is observed that the switching voltage (V) decreases with increasing Si content up to x = 3 (average coordination number < r > = 2.46). Above x = 3, a turn around is seen in the composition dependence of V-t and it increases with "x" thereafter. The increase in V-t culminates in a maximum at x = 8 (< r > = 2.56). As per the information available in literature, the composition dependence of switching voltages in chalcogenide glasses are influenced by two topological thresholds namely rigidity percolation threshold (RPT) and chemical threshold (CT) respectively. It is likely that the observed turn around and maximum in the composition dependence of V-t are associated with rigidity percolation in the system.