In Situ Temperature-Dependent Transmission Electron Microscopy Studies of Psedobinary mGeTe center dot Bi2Te3 (m=3-8) Nanowires and First-Principles Calculations
SCIE
SCOPUS
- Title
- In Situ Temperature-Dependent Transmission Electron Microscopy Studies of Psedobinary mGeTe center dot Bi2Te3 (m=3-8) Nanowires and First-Principles Calculations
- Authors
- Chan Su Jung; Han Sung Kim; Hyung Soon Im; Kidong Park; Jeunghee Park; Jae-Pyoung Ahn; Yoo, SJ; Jin-Gyu Kim; Jae Nyeong Kim; Shim, JH
- Date Issued
- 2015-06
- Publisher
- AMER CHEMICAL SOC
- Abstract
- 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.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/26660
- DOI
- 10.1021/ACS.NANOLETT.5B00755
- ISSN
- 1530-6984
- Article Type
- Article
- Citation
- NANO LETTERS, vol. 15, no. 6, page. 3923 - 3930, 2015-06
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