Sensing capability of TiO2 thin films with different thicknesses as sensing membrane of EGFET pH sensor

For this research, titanium dioxide (TiO₂) is used as the sensing membrane and the thickness of the sensing membrane is varied to study the influence of thickness of sensing membrane towards EGFET pH sensor sensitivity. TiO₂ sensing membrane in form of thin film was deposited on an indium tin oxide (ITO) substrate where sol-gel spin coating technique was chosen as the depositing technique. Result shows that increasing thickness will increase the thin film surface roughness. All samples have linearity approximately 1 which indicates that TiO₂ is suitable and stable to be used to detect hydrogen ion in solution with different pH values. The sample sensitivity was measured and the result shows that the thinnest sample has the highest sensitivity with value of 56 mV/pH. This value is close to Nernstian theoretical value of 59 mV/pH.