ORGANOTIN FILMS DEPOSITED BY LASER-INDUCED CVD AS ACTIVE LAYERS IN CHEMICAL GAS SENSORS

In this work, an organotin film obtained by L-CVD at 193 nm from tetra methyltin was used as active layer in a conductometric gas sensor. As it was stated by in situ surface analysis, the 'as deposited' material contained Sn and C. However, exposure to a large dose of O-2 Or air d etermined the formation of a thin SnO2 layer covering the remaining fi lm, which was less oxidised and had an oxygen concentration gradient i n its depth. Electrical tests of the sensors showed high sensitivity a nd short response time for the detection of NO2. Satisfactory performa nces were observed also with reducing gases. In this case, the high se nsitivity measured for H-2 and ethanol, in comparison to CO and hydroc arbons, indicated the possibility to use the sensor for selective reve lation. (C) 1998 Elsevier Science S.A. All rights reserved.