Conference Papers

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Author: search.filters.author.Munga, P.

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    Thermal stability and crystallization kinetics of Bi doped Si15Te85-xBix (0 ≤ x ≤ 2) chalcogenide glassy alloys
    (Elsevier Ltd, 2018) Fernandes, B.; Munga, P.; Ramesh, K.; Udayashankar, N.K.
    Bulk Si15Te85-xBix (0 ≤ x ≤ 2) chalcogenide glassy alloys were prepared by well-established melt quenching technique. Thermal stability and crystallization kinetics of these alloys were investigated by employing differential scanning calorimetry (DSC) technique at different heating rates, namely, 10, 15, 20 and 25 K/min under non-isothermal condition. Thermal parameters such as glass transition (Tg), onset crystallization (Tc) and peak crystallization (Tp) temperatures were observed. Double crystallization peaks observed in the DSC thermogram refer to the instability and phase separated network in the glasses. Various kinetic parameters such as thermal stability (ΔT), enthalpy (ΔHc), entropy (ΔS), specific heat (ΔCp) and fragility index are deduced. The calculated kinetic parameters suggest that the stability of glassy samples decreases with the increase in Bi addition. The activation energies of glass transition (Eg), and crystallization (Ec) are calculated using relevant kinetic formulae. We further discuss on the kinetics of the synthesized materials relevant for their applications in phase change memory (PCM) material. © 2017 Elsevier Ltd.
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    Electrical switching and thermal behavior of ternary Si15Te85-xBix (0 ≤ x ≤ 2) chalcogenide glasses
    (Elsevier Ltd, 2018) Fernandes, B.; Munga, P.; Ramesh, K.; Udayashankar, N.K.
    Bulk semiconducting Si15Te85-xBix(0 ≤ x ≤ 2) chalcogenide glasses have been prepared using a well established melt-quenching technique. Electrical switching studies have been undertaken on Si15Te85-xBix(0 ≤ x ≤ 2) chalcogenide glasses. The results indicate that these samples exhibit memory type electrical switching behavior. It has been observed that the switching voltage VT of the glasses decreases with the addition of Bi. In addition, thermal stability and OFF state resistivity of the samples have been found to decrease with the increase in Bi concentration and are related to the observed decrease in switching voltages. The switching voltage (VT) has been found to increase with the thickness of the sample and decrease with increase in temperature confirming the thermal origin of the memory switching process. Further, scanning electron microscopy (SEM) studies reveal the formation of a crystalline channel indicating the conducting path between the two electrodes in the switched region. © 2018 Elsevier Ltd. All rights reserved.