All-silicon thermoelectric micro/nanogenerator including a heat exchanger for harvesting applications

This paper describes a specific route for the complete integration of a novel planar thermoelectric micro generator (mu TEG) that can operate under environmental conditions using commercial miniaturized heat exchangers. The proposed heat exchanger integration process is compatible with the fragility of planar micro machined silicon structures. The main structure of the mu TEG is built around a micromachined silicon platform defined by silicon microfabrication technologies. Different silicon-based materials, such as bottom-up grown silicon and silicon-germanium nanowire arrays as well as top-down fabricated silicon microbeams are used as thermoelectric materials. mu TEGs with those materials are characterized both before and after heat exchanger integration. The presence of the heat exchanger increases the mu TEG performance significantly and power densities around 40 W cm(-2) are obtained when placed on a heat source at 100 degrees C and exposed under natural convection to a surrounding ambient at room temperature.