Department of Chemistry, Korea University, Jochiwon 339-700, Korea.
Nano Lett. 2013 Feb 13;13(2):543-9. doi: 10.1021/nl304056k. Epub 2013 Jan 22.
Scaling-down of phase change materials to a nanowire (NW) geometry is critical to a fast switching speed of nonvolatile memory devices. Herein, we report novel composition-phase-tuned GeSbTe NWs, synthesized by a chemical vapor transport method, which guarantees promising applications in the field of nanoscale electric devices. As the Sb content increased, they showed a distinctive rhombohedral-cubic-rhombohedral phase evolution. Remarkable superlattice structures were identified for the Ge(8)Sb(2)Te(11), Ge(3)Sb(2)Te(6), Ge(3)Sb(8)Te(6), and Ge(2)Sb(7)Te(4) NWs. The coexisting cubic-rhombohedral phase Ge(3)Sb(2)Te(6) NWs exhibited an exclusively uniform superlattice structure consisting of 2.2 nm period slabs. The rhombohedral phase Ge(3)Sb(8)Te(6) and Ge(2)Sb(7)Te(4) NWs adopted an innovative structure; 3Sb(2) layers intercalated the Ge(3)Sb(2)Te(6) and Ge(2)Sb(1)Te(4) domains, respectively, producing 3.4 and 2.7 nm period slabs. The current-voltage measurement of the individual NW revealed that the vacancy layers of Ge(8)Sb(2)Te(11) and Ge(3)Sb(2)Te(6) decreased the electrical conductivity.
将相变材料缩小到纳米线 (NW) 几何形状对于非易失性存储器件的快速切换速度至关重要。在此，我们报告了通过化学气相输运方法合成的新型组成-相调谐 GeSbTe NWs，这保证了它们在纳米尺度电子器件领域的有前景的应用。随着 Sb 含量的增加，它们表现出独特的菱方-立方-菱方相演变。对于 Ge(8)Sb(2)Te(11)、Ge(3)Sb(2)Te(6)、Ge(3)Sb(8)Te(6)和 Ge(2)Sb(7)Te(4)NWs，鉴定出了显著的超晶格结构。共存在的立方-菱方相 Ge(3)Sb(2)Te(6) NWs表现出由 2.2nm 周期片组成的独特均匀超晶格结构。菱方相 Ge(3)Sb(8)Te(6)和 Ge(2)Sb(7)Te(4)NWs采用了一种创新结构；3Sb(2)层分别插入 Ge(3)Sb(2)Te(6)和 Ge(2)Sb(1)Te(4)畴，产生 3.4nm 和 2.7nm 周期片。对单个 NW 的电流-电压测量表明，Ge(8)Sb(2)Te(11)和 Ge(3)Sb(2)Te(6)的空位层降低了电导率。
