Zinc oxide thin-film chemical sensors in conjunction with neural network pattern recognition for trimethylamine and dimethylamine gases

Transient response curves for exposure to several gases are observed using zinc oxide (ZnO) thin-film gas sensors. It is found that an aluminium-doped ZnO (ZnO:Al) sensor exhibits a high sensitivity and an excellent selectivity for amine gases. In order to discriminate between gas species such as trimethylamine (TMA), dimethylamine (DMA) and other gases pattern recognition analysis using a neural network is carried out using parameters which characterize the transient responses of the sensor for exposure to gases. The recognition probability of the neural network is 90% for TMA and DMA with constant concentration and is 100% for TMA and DMA with different concentrations, except for a concentration of 1 p.p.m.