Influence of hole mobility on the response characteristics of p-type nickel oxide thin film based glucose biosensor

By Tyagi, Manisha; Tomar, Monika & Gupta, Vinay
Published in Analytica Chimica Acta NULL 2012

Abstract

RF sputtered p-type nickel oxide (NiO) thin film exhibiting tunable semiconductor character which in turns enhanced its functional properties. NiO thin film with high hole mobility is developed as a potential matrix for the realization of glucose biosensor. NiO thin film prepared under the optimized deposition conditions offer good electrical conductivity (1.5 X 10-3 Ω-1-cm-1) with high hole mobility (2.8 cm2 V-1 s-1). The bioelectrode (GOx/NiO/ITO/glass) exhibits a low value of Michaelis–Menten constant (Km = 1.05 mM), indicating high affinity of the immobilized GOx toward the analyte (glucose). Due to the high surface coverage (2.32 X 10-7 mol cm-2) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1 mA (mM-1-cm-2) and a good linearity from 25 to 300 mg dL-1 of glucose concentration with fast response time of 5 s. Various functional properties of the material (mobility, crystallinity and stress) are found to influence the charge communication feature of NiO thin film matrix to a great extent, resulting in enhanced sensing response characteristics.

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