Universität zu Köln

Choi, Minho, Choi, Heechae ORCID: 0000-0002-9390-6607, Ahn, Jinho and Kim, Yong Tae (2019). Interface-Driven Phase Transition of Phase-Change Material. Cryst. Growth Des., 19 (4). S. 2123 - 2131. WASHINGTON: AMER CHEMICAL SOC. ISSN 1528-7505

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Abstract

In order to be able to control the phase transition of engineered phase-change materials, the specific understanding of phase transition processes is essential. To understand the effect of dopant on phase transition, the phase transition processes of Bi-5.5(In3SbTe2)(94.5) (Bi-IST) are quantitatively investigated with regard to the interfacial, bulk, entropy, and Gibbs free energies involved in the intermediate InSb and InTe phases and the crystallized Bi-IST. In the first step, InSb is crystallized; InTe and Bi are present in the amorphous phase. In the second step, heterogeneous nucleation of crystalline InTe occurs on the InSb. The energy barrier calculated for this nucleation of crystalline InTe is reduced by 1.5 times owing to the interfacial reaction of 5.5 atom % of Bi atoms compared to the case without Bi. In the third step, crystalline InSb and InTe are crystallized to Bi-IST since Bi atoms substitute Sb sites with a higher interfacial energy. The difference in the Gibbs free energy of the Bi-IST is -1.4 x 10(5) eV, which is lower than the -1.1 x 10(5) eV of the IST; this is because the differences in entropy with an increase in temperature and the interfacial energy are increased owing to the added Bi atoms. This lower Gibbs free energy becomes a driving force for the stable phase transition of Bi-IST at a lower transition temperature compared with that of the IST. With these phase transition processes, the contribution shares of enthalpy, entropy with temperature change, and interfacial energy are quantitatively analyzed; moreover, we recommend one of the various methods to design a novel phase-change material.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Choi, Minho UNSPECIFIED UNSPECIFIED UNSPECIFIED Choi, Heechae UNSPECIFIED orcid.org/0000-0002-9390-6607 UNSPECIFIED Ahn, Jinho UNSPECIFIED UNSPECIFIED UNSPECIFIED Kim, Yong Tae UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-152011
DOI:	10.1021/acs.cgd.8b01690
Journal or Publication Title:	Cryst. Growth Des.
Volume:	19
Number:	4
Page Range:	S. 2123 - 2131
Date:	2019
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1528-7505
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GENERALIZED GRADIENT APPROXIMATION; GE-SB-TE; HETEROGENEOUS NUCLEATION; THIN-FILMS; THERMODYNAMIC PROPERTIES; GE2SB2TE5 FILMS; RESISTANCE; DYNAMICS; DIAGRAM; GROWTH Multiple languages Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15201