$SnO_2$ thin films were deposited on glass substrates and were fabricated as a conduction modulation type sensor. The sensor was designed with electrodes which enables the application of electric field normal to the surface of $SnO_2$ film.
The sensing characteristics of the device was tested using CO and $H_2$ gas and linear response to the concentration of each gas and also to the mixture of the CO and $H_2$ were detected. The carrier gas of the gases being detected was synthetic air.
The electric field was applied and was observed to effect the conductivity of the $SnO_2$ film and the electric field versus conductivity plot showed different behavior with varying gas composition. Also the application of the electric field was found to reduce the history effect by the residual gas on $SnO_2$ film surface.
