Characterization of ZnO/TiO2 bilayer film for extended gate field-effect transistor (EGFET) based PH sensor

Abstract

An extended gate field-effect transistor (EGFET) of ZnO/TiO2 bilayer film as pH sensor was demonstrated in this paper. The sol-gel zinc oxide (ZnO) and titanium dioxide (TiO2) were prepared and spin coated onto indium tin oxide (ITO) coated glass substrate. After deposition process, this bilayer film then was annealed from 200°C up to 700°C. EGFET measurement employed to obtain the sensitivity of the bilayer thin film towards pH buffer solution, which is pH4, pH7 and pH10. According to the measurement process, we obtained that bilayer film annealed at 400°C produced highest sensitivity among other bilayer film, which is 66.8 mV/pH.