Gutiérrez Monreal, JavierArés Escolar, LuisRobla Villalba, José IgnacioHorrillo Guemes, María CarmenSayago Olmo, IsabelAgapito Serrano, Juan Andrés2023-06-202023-06-2019920925-400510.1016/0925-4005(92)85023-Phttps://hdl.handle.net/20.500.14352/60074Copyright © 1992 Published by Elsevier B.V. Symposium B: New Materials, Physics & Technologies for Micronic Integrated Sensors The authors will like to thank COPRECI (FAGOR S. Cop.) Mondragón (Spain) for the finantial support in this researchElectrical properties of polycrystalline gas sensors are analyzed by d.c. and a.c. measurements. d.c. electrical conductivity values compared with those obtained by admittance spectroscopy methods help to obtain a detailed 'on line' analysis of conductivity-modulated gas sensors. The electrical behaviour of grain boundaries is obtained and a new design of sensors can be achieved by enhancing the activity of surface states in the detecting operation. A Schottky barrier model is used to explain the grain boundary action under the presence of surrounding gases. The height of this barrier is a function of gas concentration due to the trapping of excess charge generated by gas adsorption at the interface. A comparison between this dependence, and a plot of the real and imaginary components of the admittance versus frequency at different gas concentrations, provides information on the different parameters that play a role in the conduction mechanisms. These methods have been applied to the design of a CO sensor based on tin oxide films for domestic purposes, the characteristics of which are presented.engjournal articlehttp://dx.doi.org/10.1016/0925-4005(92)85023-Phttp://www.sciencedirect.com/open access537Gas sensorPollutionSnO2Electrónica (Física)