Pure TiO₂/PSi and TiO₂@Ag/PSi structures as controllable sensor for toxic gases

Abstract

In this research, two pellets of titanium dioxide TiO2 were prepared at room temperature. The first was pure titanium dioxide, and the other was doped with silver (2.5%). The pellets were deposited on porous silicon (PSi) with the pulsed laser deposition (PLD) technique. The results of scanning electron microscopy and energy-dispersive X-ray spectroscopy showed improvements in the surface morphologies of the TiO2/PSi and TiO2@Ag/PSi composites. The composites were then tested as CO2 gas sensors. The electrical measurements of the composites showed a decrease in the electrical resistance of the CO2 gas sensor doped with a metal. Sensitivity to CO2 increased to up to 55% in Ag-doped TiO2 film with a concentration of 2.5%, and the highest sensitivity value was obtained in the pure titanium dioxide film (26%).

Keywords

• porous silicon
• photo-electrochemical etching
• titanium oxide
• pulsed laser deposition
• sensitivity
• gas sensor