High quality thin films of thermoelectric misfit cobalt oxides prepared by a chemical solution method

• Published in: Scientific reports Vol. 5; no. 1; p. 11889
• Main Authors: Rivas-Murias, Beatriz, Manuel Vila-Fungueiriño, José, Rivadulla, Francisco
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 08.07.2015; Nature Publishing Group
• Subjects: 142/126; 639/301/299/2736; 639/638/263/915; Chemical composition; Cobalt; Crystals; Electrical conductivity; Humanities and Social Sciences; Integration; Interfaces; multidisciplinary; Oxides; Science; Temperature effects; Thin films; Vacuum
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep11889

Misfit cobaltates ([Bi/Ba/Sr/Ca/CoO] n RS [CoO2] q ) constitute the most promising family of thermoelectric oxides for high temperature energy harvesting. However, their complex structure and chemical composition makes extremely challenging their deposition by high-vacuum physical techniques. Therefore, many of them have not been prepared as thin films until now. Here we report the synthesis of high-quality epitaxial thin films of the most representative members of this family of compounds by a water-based chemical solution deposition method. The films show an exceptional crystalline quality, with an electrical conductivity and thermopower comparable to single crystals. These properties are linked to the epitaxial matching of the rock-salt layers of the structure to the substrate, producing clean interfaces free of amorphous phases. This is an important step forward for the integration of these materials with complementary n-type thermoelectric oxides in multilayer nanostructures.