Department of Physics, Engineering and Astronomy, Austin Peay State University, Clarksville, TN, 37044, USA.
Department of Nanoscience, University of North Carolina, Greensboro, NC, 27401, USA.
Sci Rep. 2023 Feb 18;13(1):2881. doi: 10.1038/s41598-023-30160-7.
Phase-change materials, demonstrating a rapid switching between two distinct states with a sharp contrast in electrical, optical or magnetic properties, are vital for modern photonic and electronic devices. To date, this effect is observed in chalcogenide compounds based on Se, Te or both, and most recently in stoichiometric SbS composition. Yet, to achieve best integrability into modern photonics and electronics, the mixed S/Se/Te phase change medium is needed, which would allow a wide tuning range for such important physical properties as vitreous phase stability, radiation and photo-sensitivity, optical gap, electrical and thermal conductivity, non-linear optical effects, as well as the possibility of structural modification at nanoscale. In this work, a thermally-induced high-to-low resistivity switching below 200 °C is demonstrated in Sb-rich equichalcogenides (containing S, Se and Te in equal proportions). The nanoscale mechanism is associated with interchange between tetrahedral and octahedral coordination of Ge and Sb atoms, substitution of Te in the nearest Ge environment by S or Se, and Sb-Ge/Sb bonds formation upon further annealing. The material can be integrated into chalcogenide-based multifunctional platforms, neuromorphic computational systems, photonic devices and sensors.
相变材料在电、光或磁性能上表现出两种截然不同状态之间的快速切换，这对现代光子学和电子学设备至关重要。迄今为止，这种效应在基于 Se、Te 或两者的硫属化合物以及最近的化学计量 SbS 组成中得到了观察。然而，为了实现与现代光子学和电子学的最佳集成，需要混合 S/Se/Te 相变介质，这将允许对玻璃相稳定性、辐射和光敏感性、光学带隙、电导率和热导率、非线性光学效应等重要物理性质进行广泛调谐，以及在纳米尺度上进行结构改性的可能性。在这项工作中，在富 Sb 的等硫属化物（含有 S、Se 和 Te 比例相等）中演示了低于 200°C 的热诱导高到低电阻率切换。纳米级机制与 Ge 和 Sb 原子的四面体和八面体配位之间的交换、最近的 Ge 环境中 Te 被 S 或 Se 取代以及进一步退火时 Sb-Ge/Sb 键的形成有关。该材料可以集成到基于硫属化物的多功能平台、神经形态计算系统、光子器件和传感器中。
