Gas Sensing Property of Perovskite SrTi_1−x Fe _x O_3−δ Fabricated by Thick Film Planar Technology

Planar sensor of SrTi_1−x Fe _x O_3−δ , x = 0.4 and 0.6, with perovskite structure was fabricated on alumina substrate using thick film technology. Electrical resistance was measured as a function of thermal treatment conditions, atmosphere, time and temperature. Sensing property was also measured as a function of temperature and the gases of O₂, CH₄, CO, CO₂, NO and NO₂. The resistance of SrTi_1−x Fe _x O_3−δ is lower than those of SrTiO₃ or SrFeO₃. TCR (temperature coefficient of resistance) of zero over 550 °C was measured for the composition of SrTi_1−x Fe _x O_3−δ after thermal treatment at 1100 °C in air atmosphere only. The perovskite SrTi_1−x Fe _x O_3−δ didn't show any response to CH₄, CO, CO₂, NO and NO₂, but an excellent response and recovery characteristics with oxygen concentration.