Gas sensing properties of doped copper oxide (CuO) thin films and nanostructures.

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dc.contributor.authorMnethu, Ongezwa
dc.date.accessioned2023-03-14T10:35:08Z
dc.date.available2023-03-14T10:35:08Z
dc.date.issued2021
dc.descriptionA thesis submitted to the Faculty of Science and Agriculture in fulfilment of the requirements for the Degree of Master of Physics in the Department of Physics and Engineering at the University of Zululand, South Africa, 2021.en_US
dc.description.abstractp-xylene is a harmful volatile organic compound that needs to be tested for indoor air quality detection. We report on the sensing characteristics of CuO and Zn doped CuO nanoplatelets of various concentrations that were prepared by hydrothermal synthesis, against nine different gases. These CuO and Zn based nanoplatelets were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence emission and vibrating sample magnetometer measurements. CuO and 0.1 at. % Zn doped CuO samples were most sensitive and selective to p-xylene gas with relatively high responses (Ra/Rg ratio) of about 42 and 53 at an operating temperature of 150 °C, respectively. These responses were about six times higher compared to the other 8 tested interfering gases. All these samples further exhibited a paramagnetic behavior at room temperature, due to small traces of point defects, such as oxygen vacancies. Both these sensor materials did not show green luminescence at room temperature that is normally associated with oxygen vacancies. However, temperature dependent photoluminescence (PL) measurements for the 0.1 at. % Zn doped CuO showed broad visible emission, including green luminescence, which increased with temperature up to 150 °C and coincided with the gas sensing temperature. The pure CuO, however, showed a rapid quenching in PL emission with an increase in the temperature up to 150 °C. Nevertheless, both pure CuO and 0.1 at. % Zn doped CuO based sensors were highly sensitive to the p-xylene gas. The mechanism associated to the xylene superior sensing was considered in terms of point defects and surface area as active sites for adsorption of gas molecules.Keywords: CuO, Gas sensor, Thin films and nanostructures, Gas sensing properties.
dc.description.sponsorshipNational research foundation.en_US
dc.identifier.urihttps://hdl.handle.net/10530/2312
dc.language.isoenen_US
dc.publisherUniversity of Zululand
dc.subjectHydrothermal synthesisen_US
dc.subjectGas sensing propertiesen_US
dc.subjectGas sensoren_US
dc.subjectThin films and nanostructuresen_US
dc.titleGas sensing properties of doped copper oxide (CuO) thin films and nanostructures.en_US
dc.typeThesisen_US
dcterms.abstractP-xylene is a harmful volatile organic compound that needs to be tested for indoor air quality detection. We report on the sensing characteristics of CuO and Zn doped CuO nanoplatelets of various concentrations that were prepared by hydrothermal synthesis, against nine different gases. These CuO and Zn based nanoplatelets were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence emission and vibrating sample magnetometer measurements. CuO and 0.1 at. % Zn doped CuO samples were most sensitive and selective to p-xylene gas with relatively high responses (Ra/Rg ratio) of about 42 and 53 at an operating temperature of 150 °C, respectively. These responses were about six times higher compared to the other 8 tested interfering gases. All these samples further exhibited a paramagnetic behavior at room temperature, due to small traces of point defects, such as oxygen vacancies. Both these sensor materials did not show green luminescence at room temperature that is normally associated with oxygen vacancies. However, temperature dependent photoluminescence (PL) measurements for the 0.1 at. % Zn doped CuO showed broad visible emission, including green luminescence, which increased with temperature up to 150 °C and coincided with the gas sensing temperature. The pure CuO, however, showed a rapid quenching in PL emission with an increase in the temperature up to 150 °C. Nevertheless, both pure CuO and 0.1 at. % Zn doped CuO based sensors were highly sensitive to the p-xylene gas. The mechanism associated to the xylene superior sensing was considered in terms of point defects and surface area as active sites for adsorption of gas molecules. Keywords: CuO, Gas sensor, Thin films and nanostructures, Gas sensing properties.
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