Low-temperature fabrication of pyroelectric Ba0.8Sr0.2TiO3 thin films by asol-gel process

Ba0.8Sr0.2TiO3 films were fabricated with a 0.05 M solution by a sol-gel pr ocess at temperatures between 550 and 650 degreesC. Analysis by x-ray diffr action, Raman spectroscopy, and scanning electron microscopy revealed that the films annealed at 650 degreesC showed pure perovskite phase, tetragonal structure, and columnar grains with an average grain size of 150 nm. Elect rical measurements performed on the films annealed at 650 degreesC showed t wo dielectric peaks in the dielectric constant-temperature curve, a remnant polarization of 1.4 muC/cm(2), a coercive field of 18.3 kV/cm, and good in sulating property. The measured pyroelectric coefficient for the films anne aled at 650 degreesC was larger than 3.1 x 10(-4) C/m(2)K at the temperatur es ranging from 10 to 26 degreesC and reached the maximum value of 4.1 x 10 (-4) C/m(2)K at 16 degreesC. The excellent pyroelectric property rendered t he Ba0.8Sr0.2TiO3 films annealed at 650 degreesC promising for uncooled inf rared detectors and thermal imaging applications.