pH sensing characteristics of EGFET based on Pd-doped ZnO thin films synthesized by sol-gel method

This work presents the fabrication and characterization of Palladium-doped Zinc Oxide (Pd-ZnO) thin films for Extended-Gate Field-Effect Transistor (EGFET) pH sensor. The films were fabricated on p-type silicon Si(111) substrates using sol-gel technique. The structure, surface morphology, and electrical properties Pd-ZnO films were studied. The doped ZnO films have uniform, homogenous and free of cracks surfaces. The prepared films were used as pH sensor head to immerse into buffer solutions with different pH. The sensing performance of the fabricated films increased with increasing the doping concentration. The 4% Pd-doped ZnO film based EGFET sensor exhibited voltage sensitivity of 27.86 mV/pH and linearity of 0.97855 in the linear region with pH range from (5-11) which was better than the 2% Pd-doped ZnO based EGFET sensor voltage sensitivity of 24.41 mV/pH and linearity of 0.97746.