A novel approach has been presented using a sensor model to study the sensing response of magnetic tunneling transistor (MTT) as a highly sensitive hydrogen gas sensor. We have shown that when MTT was exposed to hydrogen gas the magnetization of upper ferromagnetic layer (emitter) decreased resulting in a decrease in spin polarization of the electrons in the layer which creates higher collector current in the circuit. We conducted a sensor model using simulation of the device to examine the effect of the Schottky barrier of the collector-base junction on the sensor response towards various hydrogen concentrations. An interesting result of the simulation was a very high response of 13.7 times increase in sensing response of the device with Schottky barrier subjected to a very low concentration of hydrogen compared to the device without Schottky barrier, exhibiting the high performance of MTT sensor for detection of very low hydrogen concentrations. Further, the relation between the response of MTT sensor and the thickness of the insulator barrier of emitter-base magnetic tunneling junction was also investigated. The sensing response of MTT sensor was inversely related to the insulator barrier thickness and a higher gas response was obtained for thinner insulator layers.
