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Non-linear I-V behavior and electrical switching exhibited by chalcogenide glassy semiconductors, find applications in variety of areas including information storage and power control. In this work, semiconducting chalcogenide As40Te60-xInx glasses have been prepared by melt quenching technique. The current-voltage and electrical switching behavior of these glasses have been studied using a custom-built PC based system. The results obtained clearly indicate that all the glasses studied exhibit current controlled negative resistance behavior, which leads to the low resistance state. The switching to the low resistance estate is found to be reversible and the samples revert back to the high resistance state on reducing the current. Threshold switching over such a wide range of compositions has been observed only in very few systems so far. The most interesting outcome of the present studies is the variation of the switching voltage with composition. It is observed that there is an increase in the switching voltage Vt with the increase in indium concentration in the composition range 7.5 <EQ x <EQ 12.5. Further, the composition dependence of switching field is found to exhibit a distinct change in slope at x equals 12.5 and Vt continues to increase with x until x equals 13.5. Around x equals 13.5, the trend is reversed and Vt starts decreasing with x. A minimum in Vt is seen around the composition x equals 14.3, which corresponds to the chemical threshold of the As-Te-In system. Beyond x equals 14.3, switching voltage is found to increase with composition again. The present result are consistent with earlier observations, which indicate the composition dependence of switching voltages of chalcogenide glasses are influenced by chemical ordering and rigidity percolation.
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