Spontaneous formation of nanostructures during pulsed laser deposition of epitaxial half-Heusler TiNiSn on MgO(001)
Spontaneous formation of nanostructures during pulsed laser deposition of epitaxial half-Heusler TiNiSn on MgO(001)
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DOI：
10.1063/1.5052361
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发表时间：
2019-01-01
期刊：
影响因子：
6.1
通讯作者：
MacLaren, D. A.
中科院分区：
文献类型：
--
作者：
Webster, R. W. H.;Halpin, J. E.;MacLaren, D. A.
半Heusler合金TiNiSn是一种有前途的热电应用材料，价格低廉，无毒。我们展示了平滑的TiNiSn薄膜的外延生长MgO（001）单晶衬底上的脉冲激光沉积，使用透射电子显微镜，以研究纳米级的结构和化学不均匀性。特别地，界面反应导致在衬底界面处形成富钛氧化物纳米层，并且这维持外延但扰乱膜组成。在整个膜中观察到偏析效应，产生窄范围的非化学计量的半Heusler组合物。钛氧化的倾向也导致寄生氧化钛纳米结构的相称形成，其在本体技术中可能被忽视，但却是驱动富Ni的全Heusler相的形成和半Heusler的局部分解以形成另外的镍-锡化物相的关键特征。(C)2018年作者。
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. (C) 2018 Author(s).