SnO2 gas sensor films deposited by pulsed laser ablation

Pulsed laser ablation deposition (PLAD) was used to produce SnO2 thin films, which had high sensitivity to 60 ppm ethanol in air with short response and recovery times. The maximum sensitivity was achieved at 300 degrees C. According to an equation for conductance proposed by Morrison, values of the Schottky barriers, eV(s) between the adjacent grains were calculated from measured resistance values as a function of temperature. At temperature below 423 K and above 648 K, nearly constant eV(s) values were obtained, but between the two temperatures, eV(s) increased linearly with temperature. The dependence of film resistance, R, on ethanol concentration in air, p, satisfied a power law equation, R-(p) = R-(p=0) p(-beta), with the values of exponent beta were both 0.35 at 250 degrees C and 300 degrees C. (C) 1999 Elsevier Science S.A. All rights reserved.