Study of acidosis, neutral and alkalosis media effects on the behaviour of activated carbon threads decorated by zinc oxide using extended gate FET for glucose sensor application

Abstract

In recent times, semiconductor-carbon composite microstructure offers new prospects in bio-chemical sensor research. In this study, hexagonally structured zinc oxide micro rods (ZnOMRs) were synthesized on activated carbon threads (ACTs) using the chemical bath in the absence of a ZnO seed layer. The ZnOMRs/ACTs based extended gate field effect transistor (EGFET) was characterized as a bio-chemical sensor for pH and glucose in acidosis, neutral and alkalosis media. The ZnOMRs/ACTs based EGFET sensor exhibited glucose sensitivities in terms of reference voltage (VRef) of (20.71, 18.21, and 16.72) mV/mM and drain source current (IDS) of (29.00, 25.60, and 23.62) μA/mM for pH values of 7.2, 7.4, and 7.6, respectively, at room temperature. Thus, the glucose sensitivity of the ZnOMRs/ACTs based EGFET increased with decrease in pH, due to the increased participation of hydrogen ions in the electrochemical exchange reaction between the solution and ZnOMRs/ACTs electrode. Based on the high sensitivity, ZnOMRs/ACTs composite could be a favourable micromaterial for bio-chemical sensor applications.