Micromachined nanocrystalline SnO2 chemical gas sensors for electronic nose

MEMS-based batch fabrication compatible sol-gel synthesized mesoporous nanocrystalline SnO2 gas sensor has been developed. The SnO2 nanofilm is fabricated with the combination of polymeric sol-gel chemistry and block copolymers used as structure directing agents. The novel hydrogen sensor has a fast response time (2 s) and quick recovery time (10 s), as we] I as good sensitivity (up to 90), in comparing to other hydrogen sensors developed. The working temperature of the sensor developed can be reduced as low as 100degreesC. The low working temperature poses advantages such as lower power consumption; lower thermal induced signal shift as well as safe detection in certain environments where temperature is strictly limited. The nanocrystalline SnO2 sensor has a broad sensitivity. The developed sensor cell will be used to develop a high sensitivity and high selectivity electronic nose for harmful chemical gas detection by combining different catalysts doped SnO2 gas sensor array with fuzzy neural network. (C) 2004 Elsevier B.V. All rights reserved.