A theoretical investigation of the power-law response of metal oxide semiconductor gas sensors Ι: Schottky barrier control

This study presents a theoretical investigation of the power-law response of metal oxide semiconductor gas sensors which is characterized by a linear dependence of the sensor resistance on gas pressure or concentration in double-logarithmic plots. The connection of sensor resistance with the gas partial pressure is realized by a set of differential equations, which describe the receptor and transducer functions of metal oxide semiconductor sensors. Then, the power-law response based on the two functions has been derived to oxygen, reducing and oxidizing gases, respectively. The basic mechanism of the power-law response has been theoretically explained and found to be well consistent with our experimental results and with literature reports.