Spontaneous formation of nanostructures during pulsed laser deposition of epitaxial 2 half-Heusler TiNiSn on MgO(001)

Webster, R.W.H., Halpin, J.E., Popuri, S.R., Bos, J.-W.G. and MacLaren, D.A. (2019) Spontaneous formation of nanostructures during pulsed laser deposition of epitaxial 2 half-Heusler TiNiSn on MgO(001). APL Materials, 7(1), 013206. (doi:10.1063/1.5052361)

Webster, R.W.H., Halpin, J.E., Popuri, S.R., Bos, J.-W.G. and MacLaren, D.A. (2019) Spontaneous formation of nanostructures during pulsed laser deposition of epitaxial 2 half-Heusler TiNiSn on MgO(001). APL Materials, 7(1), 013206. (doi:10.1063/1.5052361)

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Abstract

The half-Heusler alloy TiNiSn is a promising material for thermoelectric applications that is inexpensive and non-toxic. We demonstrate the epitaxial growth of smooth TiNiSn thin films on MgO(001) single crystal substrates by pulsed laser deposition, using transmission electron microscopy to investigate nanoscale structural and chemical inhomogeneities. In particular, an interfacial reaction results in the formation of a titanium-rich oxide nanolayer at the substrate interface, and this maintains epitaxy but perturbs film composition. Segregation effects are observed throughout the film, producing a narrow range of off-stoichiometric, half-Heusler compositions. The propensity of titanium to oxidise also leads to the commensurate formation of parasitic titanium oxide nanostructures which may be overlooked in bulk techniques but are a key feature that drives both the formation of Ni-enriched, full-Heusler phases and the local decomposition of the half-Heusler to form additional nickel-stannide phases.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Halpin, Dr John and Webster, Mr Robert and MacLaren, Dr Donald
Authors: Webster, R.W.H., Halpin, J.E., Popuri, S.R., Bos, J.-W.G., and MacLaren, D.A.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:APL Materials
Publisher:American Institute of Physics
ISSN:2166-532X
ISSN (Online):2166-532X
Published Online:17 December 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in APL Materials 7(1): 013206
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5525/gla.researchdata.711

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
707401Nanostructured half-Heuslers for thermoelectric waste heat recoveryDonald MaclarenEngineering and Physical Sciences Research Council (EPSRC)EP/N017218/1S&E P&A - PHYSICS & ASTRONOMY
738201EPSRC DTP 16/17 and 17/18Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/N509668/1R&I - RESEARCH STRATEGY & INNOVATION