Communication Dans Un Congrès Année : 2022

On the electrical properties of Ge-rich GeSbTe alloys: an experimental and numerical multi-scale approach

Résumé

Ge-rich GeSbTe (GST) alloys are attracting Phase Change Materials for future memories as their higher crystallization temperature offer an extended range of applications. The operation of these PCM depends on charge transport in their constituent inclusions of chalcogenide glasses. Such materials with various compositions have been intensely investigated over the past half century, including the typical composition of Ge2Sb2Te5 (GST). Although there is general agreement about the observed Poole Frenkel-type non-ohmicity, particular features observed and especially their interpretations vary dramatically between researchers. This is especially true for Ge-rich alloys, whose transitions result in strong chemical heterogeneities found in both the amorphous and crystalline states. As a result, we will demonstrate that identifying a specific mechanism in these alloys is difficult using only the I(V) and I(T) characteristics. Alternatively, we will demonstrate through impedance spectroscopy experiments that granular models, which describe electrical transport through conductive grains separated by insulating interfaces, can also simulate these characteristics when fed with physically sound fitting parameters. Finally, we will present a numerical simulation-based approach to modeling the dynamical conductivity of networks formed by self-assembled nano-objects in relation to these impedance spectroscopy experiments. The inter-object nano-resistance and nano-capacitance will be defined at the nano-scale by assuming inter-object charge transfer and accumulation mechanisms that can be adapted depending on the nature of the nano-objects and the surrounding medium. Because the positions and spatial arrangements of the nano-objects within the network will be taken into account, the attributes of percolating conducting routes can be extracted, classified, and compared in terms of path conductance and statistical distribution of path lengths. This developed numerical approach bridges the gap between the nano-scale and micro-scale electric properties of nano-structured materials, allowing for a better understanding of their charge transport properties.

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hal-04811732 , version 1 (29-11-2024)

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  • HAL Id : hal-04811732 , version 1

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Jérémie Grisolia, Sijia Ran, Louis Merle, Adrien Bourgine, D Benoit, et al.. On the electrical properties of Ge-rich GeSbTe alloys: an experimental and numerical multi-scale approach. GDR Chalco 1ère journée, GDR Chalco, Jun 2022, Dijon, France. ⟨hal-04811732⟩
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