Growth and structure characterization of epitaxial Bi2Sr2Co2Oy thermoelectric thin films on LaAlO3 (001)

Epitaxial Bi2Sr2Co2Oy thin films with excellent c-axis and ab-plane alignments have been grown on (001) LaAlO3 substrates by chemical solution deposition using metal acetates as starting materials. Microstructure studies show that the resulting Bi2Sr2Co2Oy films have a well-ordered layer structure with a flat and clear interface with the substrate. Scanning electron microscopy of the films reveals a step–terrace surface structure without any microcracks and pores. At room temperature, the epitaxial Bi2Sr2Co2Oy films exhibit a resistivity of about 2 mΩ cm and a seebeck coefficient of about 115 μV/K comparable to those of single crystals.