Specially environmental responses induced by multi-field coupling for nanocrystalline SnO2 porous film as gas sensor

The perspective focuses on two easily neglected phenomena: the non-linear I–V and chair-type I–t curves, by modulating the external fields (such as the operating temperature, the category of testing gas and the bias voltage). I–V curves were obtained when the sensor exposed to the methanol and ethanol at a range from 150 to 400 °C. The results show that the non-linear I–V curve appears only the sensor exposed to ethanol at the operating temperature of 300 °C, while the linear I–V curves were obtained when the sensor was operated under all other selected measuring conditions. To further study the above mentioned critical phenomenon at 300 °C, I–t curves were measured at 250–350 °C. Interestingly, both I–V and I–t experimental results display good corresponding relation: the non-linear I–V and chair-type I–t characteristics always occur at the same measuring condition. At the mechanistic level, we presented a coupling induced framework and also believed that the selective effect of segregated trapping levels was dominant responsible for these special environmental responses. The mechanism framework was verified indirectly via in situ DRIFTS technology.