Effects of the external electric field from a substrate on Cl-2 gas adsorption on SnO2 thin films

Changes in current by Cl-2 gas adsorption were measured at 200 degrees C for SnO2 films sputtered on SiO2/Si substrates, with a varying electric field from the substrate. Properties of Cl-2 adsorption, such as sensitivity and reaction rate constant, under a positive (+5 V) substrate bias were almost the same with those under 0 V bias. However, under a negative (-5 V) substrate bias, the current decreased remarkably by Cl-2 adsorption and a high sensitivity was obtained. Moreover, the reaction rate constant was found to be about 10 times or more larger than those under 0 V and +5 V with positive biases. It was indicated that an external electric field affects the adsorption behavior of Cl-2 on SnO2 surface. (C) 1996 American Institute of Physics.