Mudenda, S, Kale, GM and Hara, YRS (2014) Rapid synthesis and electrical transition in p-type delafossite CuAlO₂. Journal of Materials Chemistry C, 2 (43). pp. 9233-9239. ISSN 2050-7526
Abstract
Highly polycrystalline and pure delafossite phase CuAlO2 powder has been synthesised within a short annealing period, shorter than most conventional processes. This is an improvement over the conventional synthesis procedures. The conventional synthesis procedure has seen CuAlO2 only formed at high annealing temperatures ≥1100 °C over long annealing time, some as long as 96 hours. In the current process, a pure phase devoid of impurities has been obtained at a reduced calcination time of 1.5 hours in an argon atmosphere at a temperature of 1150 °C. This was confirmed by XRD and SEM/EDX. High temperature DC/AC electrical measurements show a change in the conduction mechanism from mixed conductivity (ionic + p-type) in the temperature range of 375 ≥ T ≥ 25 °C to intrinsic type behavior above 375 °C. The activation energies for these two regimes are 0.27 eV and 0.08 eV respectively. This change from mixed to p-type conductivity is confirmed by spectral analysis also. Spectral analysis using the power law also revealed that conduction is of long range hopping. The use of platinum as a contact electrode at elevated temperatures has a detrimental effect on the electrical properties since it encourages the formation of CuAl2O4 at the interface due to the formation of a more stable Cu–Pt alloy by virtue of the chemical reaction Image Pt+2CuAlO2→CuAl2O4+PtCu.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014 The Royal Society of Chemistry. This is an author produced version of a paper published in Journal of Materials Chemistry C. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Materials Research (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Jun 2016 09:27 |
Last Modified: | 17 Jan 2018 06:10 |
Published Version: | http://dx.doi.org/10.1039/c4tc01349b |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/c4tc01349b |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:99444 |