Chemosorption hydrogen gas sensor based on MOSFET with optical activation

In this paper we present an approach which allows to increase the sensitivity of the sensors at room temperature. Field effect transistors with SnO₂ gate in combination with optical activation of the adsorption centres on the surface were utilized. Studies of photosensitivity were carried out using a set of LEDs in the visible spectral range by the method of impedance spectroscopy. Optical activation of the adsorption centres in the SnO₂ gate leads to the additional accumulation of positive charges on top of the gate H⁺. Positive charge caused broadening of the channel in MOSFET sensor, resulting to lower real component of the impedance. These results show that optical activation allows to detect significantly lower concentrations of the hydrogen contained gases.