Effect of epitaxial strain on phase separation in thin films

Lahiri, A and Abinandanan, T A and Gururajan, M P and Bhattacharya, Saswata (2014) Effect of epitaxial strain on phase separation in thin films. Philosophical Magazine Letters, 94 (11). pp. 702-707. ISSN 0950-0839 (In Press)

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In epitaxially grown alloy thin films, spinodal decomposition may be promoted or suppressed depending on the sign of the epitaxial strain. We study this asymmetry by extending Cahn’s linear theory of spinodal decomposition to systems with a composition dependent lattice parameter and modulus (represented by Vegard’s law coefficients, (Formula presented.) and y, respectively), and an imposed (epitaxial) strain (e). We show analytically (and confirm using simulations) that the asymmetric effect of epitaxial strains arises only in elastically inhomogeneous systems. Specifically, we find good agreement between analytical and simulation results for the wave number (Formula presented.) of the fastest growing composition fluctuation. The asymmetric effect due to epitaxial strain also extends to microstructure formation: our simulations show islands of elastically softer (harder) phase with (without) a favourable imposed strain. We discuss the implications of these results to GeSi thin films on Si and Ge substrates, as well as InGaAs films on GaAs substrates.

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IITH Creators:
IITH CreatorsORCiD
Bhattacharya, SaswataUNSPECIFIED
Item Type: Article
Uncontrolled Keywords: epitaxy; phase separation; spinodal decomposition; strain energy; stress effects; thin films
Subjects: Materials Engineering > Materials engineering
Divisions: Department of Material Science Engineering
Depositing User: Team Library
Date Deposited: 16 Dec 2014 10:33
Last Modified: 29 Aug 2017 11:32
URI: http://raiith.iith.ac.in/id/eprint/1141
Publisher URL: http://dx.doi.org/10.1080/09500839.2014.968652
OA policy: http://www.sherpa.ac.uk/romeo/issn/0950-0839/
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