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Modélisations multi-physiques de la génération piézoélectrique à l'aide de nanofils d'Oxyde de Zinc

Abstract : Recent progresses in manufacturing processes allow a better control of dimensions and chemical composition of nanostructures. This leads to the emergence of a new family of devices known as Nano ElectroMechanical Systems or NEMS. These devices show novel physical properties and functionnal characteristics due to their reduced size. Besides, their operating power consumption are tiny, making the use of their environment as energy source highly attractive. The design of a generator that scavenge the surrounding energy of the NEMS is quite a challenge; indeed, such a microharvester should be small enough to ensure that the dimensions of the whole autonomous device are still acceptable. In that context, we investigate ZnO nanowires as active elements of piezoelectric nano and microgenerator. We have specially developped two models of nanowire that take into account of the piezoelectric-semiconducting coupling to appreciate its effects on the electromechanical conversion of energy. In a first step, the electromechanical conversion of energy that occurs in a ZnO nanowire that is statically and laterally deflected has been studied thanks to an analytical-numerical approach. This model highlights the interaction between the piezoelectric potential and the free charge carriers that causes screening effect. Then, the equivalent circuit of the nanowire seen as a metal/semiconductor/metal (MSM) structure, taking into account the piezoelectric effect has been designed. This approach is based on a dynamic description of the problem and could be a valuable tool to evaluate the performance of nanowires as active elements in an integrated system. These two approaches are complementary and are helpful for the physical understanding of the device operation. Moreover, it indicates tendencies to optimise the nanowires properties in sight of their use as active elements in nano and microgenerators. Finally, we shared our reflexions on the nanowires synthesis and their integration in microsystem together with the realisation and the characterisation of a nanowire based harvesting device.
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https://tel.archives-ouvertes.fr/tel-00860496
Contributor : Olivier Graton <>
Submitted on : Tuesday, September 10, 2013 - 4:18:47 PM
Last modification on : Tuesday, November 19, 2019 - 4:46:30 PM
Long-term archiving on: : Wednesday, December 11, 2013 - 4:20:46 AM

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  • HAL Id : tel-00860496, version 1

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Olivier Graton. Modélisations multi-physiques de la génération piézoélectrique à l'aide de nanofils d'Oxyde de Zinc. Micro et nanotechnologies/Microélectronique. Université François Rabelais - Tours, 2012. Français. ⟨tel-00860496⟩

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