Increasing the sensitivity and selectivity of Metal Oxide gas sensors by controlling the sensitive layer polarization

The effects of bias current on sensitivity and selectivity of resistive Metal-Oxide (MOX) sensors toward gases have been investigated. While the working temperature is kept constant, it has been found that tuning the polarization of the MOX thin film induces changes on its sensitivity toward gases. Besides, the behavior of sensitivity versus bias current depends on the nature of the gas and of the thin sensing film, meaning it is possible to enhance the selectivity by adjusting the polarization of different sensitive layers. This underutilized parameter provides a new way of improving easily gas sensors sensitivity and above all selectivity. It would then be interesting to polarize individually each sensor of a multi-sensor device in order to optimize the whole system performances, which may represent a breakthrough in the development of smart E-Nose.