Fabrication and electrical properties of sol-gel-derived Ba_0.8Sr_0.2TiO₃ ferroelectric films from a 0.05-M spin-on solution

Barium strontium titanate (Ba_0.8Sr_0.2TiO₃) films with good ferroelectricity have been obtained by a developed sol-gel processing, using a 0.05-M spin-on solution. X-ray diffraction and Raman spectroscopy investigations showed that the Ba_0.8Sr_0.2TiO₃ film exhibited a tetragonal structure at room temperature. Field-emission scanning electron microscopy measurements revealed that large columnar grains with the size of 100 to 200 nm in the film were formed from the highly dilute spin-on solution with layer-by-layer homoepitaxy. Electrical measurements for the prepared Ba_0.8Sr_0.2TiO₃ film showed a remnant polarization of 3.5 μC/cm², a coercive field of 53 kV/cm, two distinctive phase transitions, lower dissipation factor, and good insulating properties. These results indicate the sol-gel-derived Ba_0.8Sr_0.2TiO₃ film from a 0.05-M solution is suitable for uncooled infrared detector applications.