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

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 (1.5×10−3Ω−1-cm−1) with high hole mobility (2.8cm2V−1s−1). The bioelectrode (GOx/NiO/ITO/glass) exhibits a low value of Michaelis–Menten constant (Km=1.05mM), indicating high affinity of the immobilized GOx toward the analyte (glucose). Due to the high surface coverage (2.32×10−7molcm−2) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1mA(mM−1-cm−2) and a good linearity from 25 to 300mgdL−1 of glucose concentration with fast response time of 5s. 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.