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Preparation of pH Sensor Based on Extended-Gate Field-Effect Transistor with Spinel ZnCo2O4 Thin Films by Electrostatic Spray Deposition
Author(s)
Date Issued
December 1, 2023
Type
Article
Abstract
Electrostatic spray deposition was applied to prepare pH sensing with spinel ZnCO2O4 thin films based on the measurement of extended-gate field-effect transistors (EGFET). The influence of annealing temperatures on the characteristics of the prepared films was analyzed. The structural and morphological properties of the annealed ZnCo2O4 films were assessed by x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and contact angle measurement. The effect of the ZnCo2O4 annealing temperature on the characteristics of pH sensing for the prepared ZnCo2O4 films in EGFET measurement were examined with pH buffer solutions in a pH range of 2–12 at room temperature. The sensing films annealed at 550°C demonstrated a high voltage and current sensitivity at 67.6 mV/pH and 1.033 (µA)½/pH, with linearity values of 0.9968 and 0.9991, respectively. Moreover, the annealed 550°C ZnCo2O4 film exhibited low hysteresis at 4.99 mV and high retention stability. The results revealed that the pH sensing of the ZnCo2O4 EGFET device showed a super-Nernstian sensitivity, which indicated the influence of the surface properties of the annealed film. Therefore, the ZnCo2O4 film should be considered a potential option for the pH sensing layer in EGFET applications.
Citation
Journal of Electronic Materials, 52(12), 8095-8107, 2023