The effect of post-deposition annealing conditions on structural and thermoelectric properties of sputtered copper oxide films. Issue 49 (12th August 2020)

• Record Type: Journal Article
• Authors: Abinaya, Chandrasekaran; Bethke, Kevin; Andrei, Virgil; Baumann, Jonas; Pollakowski-Herrmann, Beatrix; Kanngießer, Birgit; Beckhoff, Burkhard; Vásquez, G. Cristian; Mayandi, Jeyanthinath; Finstad, Terje G.; Rademann, Klaus
• Is Part Of: RSC advances. Volume 10:Issue 49(2020)
• Page Start: 29394
• Page End: 29401
• Publication Date: 2020-08-12
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra03906c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : This study reveals the interplay between the composition and thermoelectric performance of mixed copper oxide thin films, which can be finely adjusted by varying the annealing atmosphere. Abstract : The development of thin-film thermoelectric applications in sensing and energy harvesting can benefit largely from suitable deposition methods for earth-abundant materials. In this study, p-type copper oxide thin films have been prepared on soda lime silicate glass by direct current (DC) magnetron sputtering at room temperature from a pure copper metallic target in an argon atmosphere, followed by subsequent annealing steps at 300 °C under various atmospheres, namely air (CuO:air), nitrogen (CuO:N) and oxygen (CuO:O). The resultant films have been studied to understand the influence of various annealing atmospheres on the structural, spectroscopic and thermoelectric properties. X-ray diffraction (XRD) patterns of the films showed reflexes that could be assigned to those of crystalline CuO with a thin mixed Cu (I) Cu (II) oxide, which was also observed by near edge X-ray absorption fine structure spectroscopy (NEXAFS). The positive Seebeck coefficient ( S ) reached values of up to 204 μV K −1, confirming the p-type behavior of the films. Annealing under oxygen provided a significant improvement in the electrical conductivity up to 50 S m −1, resulting in a power factor of 2 μW m −1 K −2 . The results reveal the interplay between the intrinsic composition and the thermoelectric performance of mixed copper oxide thin films, which can be finely adjusted by simply varying the annealing atmosphere.