Sol–gel-processed (001)-textured BiFeO3 thin films on Pt(111)/Ti/SiO2/Si substrates with PbO seeding nanocrystals

Abstract

50 to 200 nm-thick BiFeO₃ thin films were fabricated on Pt(111)/Ti/SiO₂/Si substrates using the sol–gel method. A PbO seeding layer was introduced between the BiFeO₃ films and the platinum electrode surface, which was found to be effective for the formation of a (001)-textured BiFeO₃ structure. A high degree of (001) orientation up to 98.3% was achieved in a 200 nm-thick film via a layer-by-layer annealing process. Cross-section images by scanning electron microscopy revealed a columnar crystal structure, which was consistent with the high texturing degree enhanced by the layer-by-layer annealing method. By investigating the dielectric, ferroelectric and piezoelectric properties of the randomly oriented and (001)-oriented films, it was revealed that significant enhancements of the dielectric and piezoelectric properties were achieved in textured samples. The texturing mechanism was also discussed.