Fabrication and thermoelectric properties of c-axis oriented nanocrystalline Bi2Sr2Co2Oy thin films

• Published in: Thin solid films 2013-05, Vol.534, p.168-171
• Main Authors: Wang, Shufang, Chen, Shanshan, Yan, Guoying, Liu, Fuqiang, Dai, Shouyu, Wang, Jianglong, Yu, Wei, Fu, Guangsheng
• Format: Article
• Language: English
• Subjects: Bi2Sr2Co2Oy; c-axis oriented; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Growth from solutions; Materials science; Methods of crystal growth; physics of crystal growth; Nanocrystalline thin films; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermoelectric effects; Thermoelectric properties; Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.02.107

c-axis oriented nanocrystalline Bi2Sr2Co2Oy thin films with the average grain size of 25nm have been achieved by chemical solution deposition combined with a rapid annealing process in oxygen. The resistivity and Seebeck coefficient of the nanostructured films are about 7.0mΩ·cm and 171μV/K at 873K, resulting in a power factor 2–3 times larger than that of the best reported value in the coarse-grained Bi2Sr2Co2Oy polycrystalline bulks. Since the thermal conductivity can be greatly reduced due to the increased phonon scattering at the grain boundaries of nanocrystalline films as well as at film surface and at film/substrate interface, great improvements in the ZT are expected in the nanocrystalline Bi2Sr2Co2Oy thin films. •c-axis oriented nanocrystalline Bi2Sr2Co2Oy thin films have been fabricated.•The nanocrystalline films exhibit a large power factor of 0.42mW/mK2 at 873K.•A small thermal conductivity is expected in the nanocrystalline films.