One-dimensional Phase-Change Nanowires for Information Storage Application

The electrically operated phase-change random access memory (PRAM) features faster write/read, improved endurance, and much simpler fabrication as compared with the traditional transistor-based nonvolatile semiconductor memories. Low-dimensional phase-change materials in nanoscale dimensions offer advantages over their bulk or thin-film counterpart in several aspects such as reduced programmable volume and reduced thermal energies in phase transition. These features contribute to low power operation, excellent scalability, and fast write/erase time. In this paper we reported a general bottom-up synthesis approach and systematic material analysis study of onedimensional chalcogenide-based phase-change materials including germanium telluride (GeTe), indium selenide (In2Se3), and germanium antimony telluride (Ge2Sb2Te5) nanowires that are targeted for nonvolatile resistive switching data storage. The phase-change nanowires have been synthesized via thermal evaporation method under vapor-liquid-solid (VLS) mechanism. The morphology, composition, and crystal structure of the synthesized nanowires were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The assynthesized nanowires are structurally uniform with single crystalline structures. The 1-D phase-change chalcogenide nanowires exhibit significantly reduced melting points, low activation energy and excellent morphology, making them promising nanomaterials for data storage devices with very low energy consumption and excellent scalability.