Fabrication and characterization of titanium dioxide based Pd/TiO2/Si MOS sensor for hydrogen gas

Abstract

Titanium dioxide (TiO2) based capacitive sensor for the detection of hydrogen gas (H2) at room temperature is reported in this paper. The metal-oxide-semiconductor (MOS) structure is fabricated on a silicon substrate with electron beam evaporated TiO2 oxide and thermally evaporated palladium (Pd) metal. The surface morphology of Pd and TiO2 films are investigated by atomic force microscopy and scanning electron microscopy. The porous Pd film is found, which is responsible for enhanced adsorption of H2. The response of MOS sensor for H2 gas is measured in the form of a shift in capacitance-voltage and conductance-voltage characteristics. The maximum sensitivities for 4% H2 gas are found as 84% and 90% in ambient air and nitrogen gas, respectively. The fabricated Pd/TiO2/Si MOS sensor shows fast response and recovery for H2 gas. The selectivity of the MOS sensor with most interfering organic vapors such as acetone, chloroform, ethanol, isopropanol, and methanol are also investigated. © 2001-2012 IEEE.