In2Se3纳米线的合成及相变机理研究

Low-dimensional phase-change nanostructures provide a valuable scientific research platform for understanding the phase-transition behavior and material thermal properties at nanoscale, in addition to their potential to achieve super-dense data storage.One-dimensional phase-change nanowires have been investigated for the fabrication of electrically operated phase change random access memory (PRAM). Among them, In2Se3 nanowire is highly promising for applications in nonvolatile data storage since it exhibits high resistivity, a resistance switching ratio of 1E5, and memory switching at much lower input power/energy than for GeTe and Ge2Sb2Te5 nanowire devices. This paper reports the preparation of α- and κ-phase In2Se3 nanowires by thermal evaporation and investigation of their phase transformations in-situ by synchrotron radiation X-ray diffraction (XRD) during a thermal annealing process. The κ-phase transformed to α-phase at 500?C and eventually transformed to high temperature α-phase with a layered structure of 5 atoms-5 atoms at 700?C irreversibly. Different atomistic structures of In2Se3 were modeled and optimized by DFT (Density Functional Theory) method, which correlates well with the synchrotron radiation XRD results. The In2Se3 nanowires also exhibit a large difference in resistivity before and after annealing.