Palladium-oxide extended gate field effect transistor as pH sensor

Abstract

In this paper, palladium thin films were deposited on the Si/SiO2/Pt substrate by using the electron beam evaporation technique, and then the films were annealed at 500 °C for one hour in an oxygen ambient to form the palladium oxide (PdO) film. The films have been tested for hydrogen ion (pH) sensing. The film was characterized by FESEM (Field-emission scanning electron microscope) and XRD (X-ray diffraction) for their morphology and structural analysis. Raman study was further done to analyze the crystallinity and the defects present in the film. XPS was done to analyze the film composition. The FESEM results confirm that the film is homogeneous and uniformly distributed over the whole sensing area. The XRD and Raman results reveal that the film is polycrystalline. XPS analysis confirms the formation of PdO. Further, the PdO nanostructure film has been explored for pH sensing. The sensitivity of the film was found to be 42.36 mV/pH. The drift characteristics of the film were also done to find out the stability of the film.

Keywords

• pH sensor
• EGFET
• Sensitivity
• PdO
• Thin film