Modelling tools for the simulation of microgenerators based on piezo-semiconducting nanowires
Résumé
Novel mechanical energy micro-harvesters using ZnO nanowire (NW) arrays as active elements have recently appeared. The electrical power generation process is based on the coupling between piezoelectric and semiconducting properties of ZnO NWs. We have developed two specific models to simulate the electromechanical conversion that occurs in mechanically activated NWs and to predict the performance of NW-based microgenerators. These models, based on two distinct approaches, take into account both the piezoelectric effect and semiconducting properties of NWs. An original analytical numerical model is dedicated to the simulation of the intrinsic electromechanical conversion that occurs in a bent NW in the presence of free charge carriers. In addition, a modelling strategy was specifically developed in order to establish a dynamic model of NW-based microgenerators without falling into the different pitfalls relative to the simulation of ZnO nanowires. These two approaches are complementary and are helpful for the physical understanding of the device operation. Moreover, it indicates tendencies to optimise the generator performance. The energy conversion efficiency is maximised for high aspect ratio NWs and an optimal concentration of impurities, both in the case of a single deformed NW and for a NW array microgenerator.
Domaines
Acoustique [physics.class-ph]
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