Modeling and simulation of zinc oxide nanowire field effect transistor biosensor

Abstract

We are presenting a three-dimensional mathematical model and simulation for zinc-oxide nanowire field effect transistor (ZnO NW-FET) biosensor for detecting streptavidin/biotin binding. Implementing previously performed physical vapor deposition (PVD) techniques, ZnO NWs were synthesized with diameters in the range of 50–120 nm and lengths of 2–7.1 µm [5]. Our model is developed by using these dimensions and incorporating a spherical molecule model with uniform charge distribution that is immersed in a solvent with mobile univalent ions as developed in [1]. Applying Poisson-Boltzmann equation for boundary and continuity conditions, expression for the electrostatic potential distribution is obtained. This distribution is used to obtain the gate voltage and develop the I–V curves for ZnO NW-FET when used as a biosensor. In the saturation region, the I–V curves demonstrate that small changes in the gate voltage leads to exponentially larger changes in the drain current and allows for single biomolecule detection.