One-Dimensional Phase-Change Nanostructure: Germanium Telluride Nanowire

High-quality nanowires of germanium telluride (GeTe), a one-dimensional chalcogenide phase-change nanostructure, were synthesized via thermal evaporation method under vapor−liquid−solid mechanism. The physical morphology, chemical composition, and crystal structure of the as-synthesized GeTe nanowires were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy. Through real-time TEM imaging of nanowire sample heated in an incrementally controllable heating system, the melting point of a single crystalline GeTe nanowire (∼40−80 nm diameter) is found to be significantly lower than that of its bulk counterpart (46% reduction, from 725 to 390 °C). The significant reduction in melting point makes one-dimensional phase-change chalcogenide nanowire a potential material for application in low-power high-density resistive switching nonvolatile data storage in which the thermal energy for material phase transition would be significantly reduced.