Multiphysics model of encapsulated piezoelectric-semiconducting nanowire with Schottky contacts and external capacitive circuit

摘要

This work presents multiphysics finite element model and results of transient analysis of both a stand-alone as well as polymer-encapsulated piezoelectric-semiconducting ZnO nanowire with Schottky contacts and external capacitive circuit. It is intended to function as a single 'piezotronic pixel' in a matrix of interconnected ZnO nanowires performing dynamic pressure sensing, which could be used in a fingerprint sensor for the ultraprecise reconstruction of the minutiae points and pores. The modeled ZnO nanowire is subjected to time-varying vertical force that is defined using either a half-harmonic or ramp-based function in order to imitate with different degree of approximation the actual pressing and release of a fingerprint sensor. Initial results of dynamic studies are presented, demonstrating variation of electrical outputs as a function of applied force amplitude and frequency, external capacitance as well as Schottky contact conditions and donor doping concentrations.