Electrical characterization of gas sensing devices based on porous TiO<INF>2</INF>

Electrical properties of two kinds of sandwich structures (SnO<INF>2</INF>:F/por-TiO<INF>2</INF>/Ti and Si/por-TiO<INF>2</INF>/Pd) are investigated by the methods of I–V, C–V characteristics and DLTS in vapors of water and alcohol. It has been demonstrated that besides the change of the conductivity and of the capacitance of the por-TiO<INF>2</INF> layers one can also use for gas sensing the change of the high frequency capacitance of the MOS type structure, measurement of the current response at relatively low frequencies and the modification of the charge transfer between the Si bulk and states near the por-TiO<INF>2</INF>/Si interface.