Effect of Ag-doping on crystal structure and high temperature thermoelectric properties of c-axis oriented Ca3Co4O9 thin films by pulsed laser deposition
Hng, Huey Hoon
Date of Issue2011
School of Materials Science and Engineering
Ag-doped Ca3Co4O9 thin films with nominal composition of Ca3−xAgxCo4O9 (x = 0∼0.4) have been prepared on sapphire (0 0 0 1) substrates by pulsed laser deposition (PLD). Structural characterizations and surface chemical states analysis have shown that Ag substitution for Ca in the thin films can be achieved with doping amount of x ≤ 0.15; while x > 0.15, excessive Ag was found as isolated and metallic species, resulting in composite structure. Based on the perfect c-axis orientation of the thin films, Ag-doping has been found to facilitate a remarkable decrease in the in-plane electrical resistivity. However, if doped beyond the substitution limit, excessive Ag was observed to severely reduce the Seebeck coefficient. Through carrier concentration adjustment by Ag-substitution, power factor of the Ag-Ca3Co4O9 thin films could reach
Journal of alloys and compounds
© 2011 Elsevier B. V. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Alloys and Compounds, Elsevier B. V.. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: http://dx.doi.org/10.1016/j.jallcom.2011.09.008 .