How to build a suspended planar thermoelectric device ?

Orateur : Dimitri TAINOFF

The use of thermoelectric devices for energy harvesting at room temperature has a lot of advantages. Indeed harvesting thermal energy, which is present all around us , could ensure connected objects (Internet of Things IoT) a real autonomy. However conventional thermoelectric modules are not well fitted to fulfill this task. Indeed even if they can be miniaturized, their 3D geometry implies a very bad exchange coefficient with their environment. This necessitates the use of heat sinks which can be much bigger than the module itself which limits the use of these modules to niche market. For more than a decade the TPS group has been working on the influence of nanostructuration on phonon transport, from low to room temperature. Several ways of manipulating and inhibiting heat flow have been studied in specific samples in the form of thin films, membranes and nanowires. This includes the study of thermal properties and their optimization in specific “electron-crystal phonon-glass” thermoelectric thin films. It also includes measurement and the understanding of phonon transport in different kinds of membranes and nanowires (Si3N4, Si). The unique experience accumulated both on phonon transport and on the elaboration and handling of suspended samples leads us to design a suspended planar thermoelectric device. Indeed one possible way of overpassing limitation of 3D module is by using membrane based planar thermoelectric devices having better exchange coefficient with their environment. However, the elaboration of such structures requires one to address scientific and technological issues. I will present a few of them including the phonon transport in nanostructured GeMn thermoelectric material and our first results concerning the elaboration of a real planar thermoelectric device.

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