Characterization of nickel/indium tin oxide based extended gate-field effect transistor as glucose sensor in acidosis, normal and alkalosis media

Abstract

This study involves the potential application of Ni/ITO thin film as a non-enzymatic glucose (NEG) sensor. The Ni thin film was deposited onto ITO substrate using DC magnetron sputtering. The structural and morphological characteristics of the as-deposited thin film were examined using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy. The sensitivity of the sensor was determined across a range of pH (acidic, neutral and alkaline) using the glucose (Glc) measuring system. The XRD spectra of the film displays a high intensity (111) peak denoting cubic crystals of Ni, while the several other distinct characteristic peaks of ITO cubic crystals. Based on the XRD analysis, the grain size of the film is 21.78 nm. The Ni/ITO thin film has a homogeneous morphology and continuous surface with very small sized nanoparticles and no cracks. The AFM topographical analysis presented a roughness value (RMS) of 3.85 nm. Moreover, Ni/ITO thin film was applied as extended-gate field-effect Transistor (EGFET) and used to estimate the pH current and voltage sensitivity (58.75 μA/pH and 61.13 mV/pH), respectively. The Ni/ITO film was implemented as EGFET, and applied as a NEG sensor. The Glc sensing characteristics of the sensor was investigated. Furthermore, the Glc sensitivities of the Ni/ITO NEG sensor under Glc range of (2–7) mM were 18.33 μA/Mm, 22.44 μA/mM and 27.57 μA/mM for acidosis, neutral and alkalosis media, respectively. The modified NEG sensor displayed a comparably better sensing performance than that reported for NiCFP in literature (3.30 μA/mM).