Structural and electrical properties of barium strontium calcium titanate thick films for uncooled IR sensors

Abstract

(Ba0.6Sr0.3Ca0.1)TiO3 powders, prepared by the sol-gel method, were mixed organic binder and the BSCT thick films were fabricated by the screen printing techniques on alumina substrates. The structural and pyroelectric properties were investigated with variation of Pr2O3 contents. All BSCT thick films, sintered at 1420 degrees C, showed the typical XRD patterns of a cubic perovskite polycrystalline structure. The average grain size of the thick film doped with 0.1 mol% Pr2O3 is 2.4 mu m and the thickness of all BSCT specimens was about 50 mu m. Relative dielectric constant and dielectric loss of the thick film doped with 0.1 mol% Pr2O3 were 4714 and 5.9%, respectively. All BSCT thick films showed the maximum pyroelectric coefficient at around the Curie temperature, and the specimen doped with 0.1 mol% Pr2O3 showed the highest value of 65.3x10(-9) C/cm(2) K. The figure of merit F.M.D-star for specific detectivity of the specimen, doped with 0.5 mol% Pr2O3, showed the good values lager than 1.0x10(-9) Ccm/J at around room temperature.