Fabrication and Characterization of Titanium Dioxide Based Pd/TiO2/Si MOS Sensor for Hydrogen Gas

Titanium dioxide (TiO
₂
) based capacitive sensor for the detection of hydrogen gas (H
₂
) at room temperature is reported in this paper. The metal-oxide-semiconductor (MOS) structure is fabricated on a silicon substrate with electron beam evaporated TiO
₂
oxide and thermally evaporated palladium (Pd) metal. The surface morphology of Pd and TiO
₂
films are investigated by atomic force microscopy and scanning electron microscopy. The porous Pd film is found, which is responsible for enhanced adsorption of H
₂
. The response of MOS sensor for H
₂
gas is measured in the form of a shift in capacitance-voltage and conductance-voltage characteristics. The maximum sensitivities for 4% H
₂
gas are found as 84% and 90% in ambient air and nitrogen gas, respectively. The fabricated Pd/TiO
₂
/Si MOS sensor shows fast response and recovery for H
₂
gas. The selectivity of the MOS sensor with most interfering organic vapors such as acetone, chloroform, ethanol, isopropanol, and methanol are also investigated.