Observation of electrical threshold switching behavior and thermal crystallization in bulk Se86-xTe14Snx chalcogenide glasses

Abstract

Selenium-rich chalcogenides have gained popularity as materials for selector devices due to their unique Ovonic Threshold Switching behavior. Bulk Se<inf>86-x</inf>Te<inf>14</inf>Sn<inf>x</inf> glassy alloys (0 ≤ x ≤ 6) were prepared through the traditional melt quenching method. The samples with Sn atomic percentage (x) = 3 to 6 are found to exhibit a rapid and reversible transition between a highly resistive and conductive state affected by an electric field. A remarkable decrement in threshold voltage (V<inf>th</inf>) from 453 V to 62 V has been observed with increase in the Tin content. Differential scanning calorimetry (DSC) analysis was carried out to understand the variation of Glass transition temperature (T<inf>g</inf>), Crystallization temperature (T<inf>c</inf>), and other important glass stability parameters and their compositional dependence. Se<inf>82</inf>Te<inf>14</inf>Sn<inf>4</inf> sample was found to be thermally most stable with Herby's parameter value (H<inf>R</inf>) of 0.3860 and a maximum number of switching cycles at room temperature. X-Ray diffraction patterns of annealed samples were compared with pristine glass to study the multi-phasic Se–Te–Sn alloy. Further, the threshold voltage (V<inf>th</inf>) and the number of threshold switching cycles are found to decrease with an increase in temperature till crystallization on-set temperature (T<inf>oc</inf>). The temperature-dependent conductivity studies showed an abrupt increase in the conductivity of the samples as the temperature crossed the crystallization onset temperature. © 2023 Elsevier Ltd and Techna Group S.r.l.