Jung, Chan Su Kim, Han Sung Im, Hyung Soon Park, Kidong Park, Jeunghee Ahn, Jae-Pyoung Yoo, Seung Jo Kim, Jin-Gyu Kim, Jae Nyeong Shim, Ji Hoon 2024-01-20T07:01:11Z 2024-01-20T07:01:11Z 2021-09-05 2015-06 1530-6984 https://pubs.kist.re.kr/handle/201004/125360 Phase-change nanowires (NWs) have emerged as critical materials for fast-switching nonvolatile memory devices. In this study, we synthesized a series of mGeTe.Bi2Te3 (GBT) pseudobinary alloy NWsGe(3)Bi(2)Te(6) (m = 3), Ge4Bi2Te7 (m = 4), Ge5Bi2Te8 (m = 5), Ge6Bi2Te9 (m = 6), and Ge8Bi2Te11 (m = 8)and investigated their composition-dependent thermal stabilities and electrical properties. As m decreases, the phase of the NWs evolves from the cubic (C) to the hexagonal (H) phase, which produces unique superlattice structures that consist of periodic 2.2-3.8 nm slabs for m = 3-8. In situ temperature-dependent transmission electron microscopy reveals the higher thermal stability of the compositions with lower m values, and a phase transition from the H phase into the single-crystalline C phase at high temperatures (400 degrees C). First-principles calculations, performed for the superlattice structures (m = 1-8) of GBT and mGeTe.Sb2Te3 (GST), show an increasing stability of the H phase (versus the C phase) with decreasing m; the difference in stability being more marked for GBT than for GST. The calculations explain remarkably the phase evolution of the GBT and GST NWs as well as the composition-dependent thermal stabilities. Measurement of the current-voltage curves for individual GBT NWs shows that the resistivity is in the range 3-25 mO.cm, and the resistivity of the H phase is lower than that of the C phase, which has been supported by the calculations. English AMER CHEMICAL SOC PHASE-CHANGE MATERIALS CHEMICAL-VAPOR-DEPOSITION CHANGE MEMORY THIN-FILMS SPEED GE2SB2TE5 CONDUCTIVITY DIFFRACTION TRANSITIONS NONVOLATILE In Situ Temperature-Dependent Transmission Electron Microscopy Studies of Psedobinary mGeTe center dot Bi2Te3 (m=3-8) Nanowires and First-Principles Calculations Article 10.1021/acs.nanolett.5b00755 1 NANO LETTERS, v.15, no.6, pp.3923 - 3930 NANO LETTERS 15 6 3923 3930 scie scopus 000356316900040 2-s2.0-84931267860 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article PHASE-CHANGE MATERIALS CHEMICAL-VAPOR-DEPOSITION CHANGE MEMORY THIN-FILMS SPEED GE2SB2TE5 CONDUCTIVITY DIFFRACTION TRANSITIONS NONVOLATILE Phase-change materials GeTe center dot Bi2Te3 nanowires superlattice electrical conductivity