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  • Ferroelastic domain organization and precursor control of size in solution-grown hafnium dioxide nanorods.

Ferroelastic domain organization and precursor control of size in solution-grown hafnium dioxide nanorods.

ACS nano (2014-04-23)
Sean W Depner, Nicholas D Cultrara, Katie E Farley, Yueling Qin, Sarbajit Banerjee
摘要

We demonstrate that the degree of branching of the alkyl (R) chain in a Hf(OR)4 precursor allows for control over the length of HfO2 nanocrystals grown by homocondensation of the metal alkoxide with a metal halide. An extended nonhydrolytic sol-gel synthesis has been developed that enables the growth of high aspect ratio monoclinic HfO2 nanorods that grow along the [100] direction. The solution-grown elongated HfO2 nanorods show remarkable organization of twin domains separated by (100) coherent twin boundaries along the length of the nanowires in a morphology reminiscent of shape memory alloys. The sequence of finely structured twin domains each spanning only a few lattice planes originates from the Martensitic transformation of the nanorods from a tetragonal to a monoclinic structure upon cooling. Such ferroelastic domain organization is uncharacteristic of metal oxides and has not thus far been observed in bulk HfO2. The morphologies observed here suggest that, upon scaling to nanometer-sized dimensions, HfO2 might exhibit mechanical properties entirely distinctive from the bulk.

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三辛基氧化膦, ReagentPlus®, 99%
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三辛基氧化膦, technical grade, 90%
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叔丁醇铪, 99.99% trace metals basis (purity excludes ~2000 ppm zirconium.)
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三辛基氧化膦, for extraction analysis, ≥98.5%
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叔丁醇铪, packaged for use in deposition systems