Design of low cost gas sensor based on SrTiO 3 and BaTiO 3 films

Abstract

We have prepared SrTiO 3/BaTiO 3 multilayer film on alumina substrates by a sol-gel technique and investigated their response for sensing ethanol vapor. The surface morphology of the films were characterized by atomic force microscope (AFM) showing that the grain size of the films increase up to 40 nm as the annealing temperature increased to 1000 ̈C. The ethanol sensors based on SrTiO 3/BaTiO 3 thin films were fabricated by applying interdigitated gold electrodes by sputtering technique. The ethanol sensing characteristics of SrTiO 3/BaTiO 3 thin films were quantified by the change in resistance of the sensors when they were exposed to ethanol. The optimum operating tempearature of these sensors was found to be 350 °C. In addition, the film annealed at 1000 ̈C exhibited p-type gas sensing behavior with the best sensitivity of 30-100 for low ethanol concentration in the range of 100-1000 ppm.