Thermoelectric property enhancement via pore confinement in template grown bismuth telluride nanowire arrays.

Author(s) Reeves, R.D.; Crosser, L.A.; Chester, G.E.; Hill, J.J.
Journal Nanotechnology
Date Published 2017 Dec 15

Nanostructuring of thermoelectric materials can lead to thermal-to-electrical conversion efficiencies comparable with mechanical energy conversion. Theory predicts that characteristic length scales of <10 nm are necessary to achieve high thermoelectric figures of merit (zT > 3). While sub-10 nm diameter nanowire arrays have been difficult to fabricate, we present here a novel template for sub-10 nm thermoelectric nanowire array fabrication using anodized aluminum oxide followed by silica wall coating for pore confinement. Electrodeposited bismuth telluride nanowires displayed increasing electrical-to-thermal conductivity ratio as the pore diameter decreased, in agreement with theoretical predictions. Achieving the desired stoichiometric ratio of Bi2Te3 through electrodeposition was non-trivial, which limited the Seebeck coefficient of the nanowires. However, hydrolysis of the nanopore walls led to improved electrodeposition, achieving near stoichiometric bismuth-to-tellurium ratios and ultimately p-type thermoelectric nanowire arrays with a Seebeck coefficient of up to 79 μV K-1.

DOI 10.1088/1361-6528/aa9733
ISSN 1361-6528
Citation Nanotechnology. 2017;28(50):505401.

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