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Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films
Superlattice-like (SLL) phase-change film is considered to be a promising phase-change material because it provides more controllabilities for the optimization of multiple performances of phase-change films. However, the mechanism by which SLL structure affects the properties of phase-change films i...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823727/ https://www.ncbi.nlm.nih.gov/pubmed/33374227 http://dx.doi.org/10.3390/nano11010020 |
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author | Qiu, Qingqian Wu, Pengzhi Hu, Yifeng Zhai, Jiwei Lai, Tianshu |
author_facet | Qiu, Qingqian Wu, Pengzhi Hu, Yifeng Zhai, Jiwei Lai, Tianshu |
author_sort | Qiu, Qingqian |
collection | PubMed |
description | Superlattice-like (SLL) phase-change film is considered to be a promising phase-change material because it provides more controllabilities for the optimization of multiple performances of phase-change films. However, the mechanism by which SLL structure affects the properties of phase-change films is not well-understood. Here, four SLL phase-change films [Ge(8)Sb(92)(15 nm)/Ge (x nm)](3) with different x are fabricated. Their behaviors of crystallization are investigated by measuring sheet resistance and coherent phonon spectroscopy, which show that the crystallization temperature (T(C)) of these films increases anomalously with x, rather than decreases as the interfacial effects model predicted. A new stress effect is proposed to explain the anomalous increase in T(C) with x. Raman spectroscopy reveals that Raman shifts of all phonon modes in SLL films deviate from their respective standard Raman shifts in stress-free crystalline films, confirming the presence of stress in SLL films. It is also shown that tensile and compressive stresses exist in Ge and Ge(8)Sb(92) layers, respectively, which agrees with the lattice mismatch between the Ge and Ge(8)Sb(92) constituent layers. It is also found that the stress reduces with increasing x. Such a thickness dependence of stress can be used to explain the increase in crystallization temperature of four SLL films with x according to stress-enhanced crystallization. Our results reveal a new mechanism to affect the crystallization behaviors of SLL phase-change films besides interfacial effect. Stress and interfacial effects actually coexist and compete in SLL films, which can be used to explain the reported anomalous change in crystallization temperature with the film thickness and cycle number of periods in SLL phase-change films. |
format | Online Article Text |
id | pubmed-7823727 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-78237272021-01-24 Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films Qiu, Qingqian Wu, Pengzhi Hu, Yifeng Zhai, Jiwei Lai, Tianshu Nanomaterials (Basel) Article Superlattice-like (SLL) phase-change film is considered to be a promising phase-change material because it provides more controllabilities for the optimization of multiple performances of phase-change films. However, the mechanism by which SLL structure affects the properties of phase-change films is not well-understood. Here, four SLL phase-change films [Ge(8)Sb(92)(15 nm)/Ge (x nm)](3) with different x are fabricated. Their behaviors of crystallization are investigated by measuring sheet resistance and coherent phonon spectroscopy, which show that the crystallization temperature (T(C)) of these films increases anomalously with x, rather than decreases as the interfacial effects model predicted. A new stress effect is proposed to explain the anomalous increase in T(C) with x. Raman spectroscopy reveals that Raman shifts of all phonon modes in SLL films deviate from their respective standard Raman shifts in stress-free crystalline films, confirming the presence of stress in SLL films. It is also shown that tensile and compressive stresses exist in Ge and Ge(8)Sb(92) layers, respectively, which agrees with the lattice mismatch between the Ge and Ge(8)Sb(92) constituent layers. It is also found that the stress reduces with increasing x. Such a thickness dependence of stress can be used to explain the increase in crystallization temperature of four SLL films with x according to stress-enhanced crystallization. Our results reveal a new mechanism to affect the crystallization behaviors of SLL phase-change films besides interfacial effect. Stress and interfacial effects actually coexist and compete in SLL films, which can be used to explain the reported anomalous change in crystallization temperature with the film thickness and cycle number of periods in SLL phase-change films. MDPI 2020-12-24 /pmc/articles/PMC7823727/ /pubmed/33374227 http://dx.doi.org/10.3390/nano11010020 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Qiu, Qingqian Wu, Pengzhi Hu, Yifeng Zhai, Jiwei Lai, Tianshu Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title | Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title_full | Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title_fullStr | Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title_full_unstemmed | Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title_short | Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge(8)Sb(92)/Ge](3) Phase-Change Films |
title_sort | mechanism of nano-structuring manipulation of the crystallization temperature of superlattice-like [ge(8)sb(92)/ge](3) phase-change films |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823727/ https://www.ncbi.nlm.nih.gov/pubmed/33374227 http://dx.doi.org/10.3390/nano11010020 |
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