Effect of density and thickness on H2-gas sensing property of sputtered SnO2 films

Undoped and Pd-doped SnO2 films were deposited under various conditions for the investigation of the effect of I'd doping, porosity, and thickness on their H-2 gas sensing properties. The temperature of the substrate and the pressure of the discharge gas were varied. All films formed were composed of columns with thicknesses between 20 and 30 nm. The film density decreased as the discharge gas pressure increased and the substrate temperature decreased. It showed values between 4.2 x 10(3) and 7.0 x 10(3) kg/m(3) depending on the deposition condition. Low film density and Pd doping resulted in high sensitivity and fast response. The largest sensitivity was observed for a Pd-doped film with a low density of 4.7 x 10(3) kg/m(3) and a thickness of 20nm. (c) 2004 Elsevier Ltd. All rights reserved.