Granulated Silicon and Thermal Energy Converters on Its Basis

Abstract

Some properties of a new modification of the well-known semiconductor material, silicon, the so-called granular silicon being a silicon powder of a given grain size whose particles are not sintered or fused but simply mechanically pressed together with a known force, have been described. Estimates of differential thermal EMF and thermal conductivity measured with metrologically certified equipment have shown that the Seebeck coefficient of this material is ten or more times higher and the thermal conductivity is approximately seven times lower than that of monocrystalline silicon, which makes it possible to consider granular silicon as a promising thermoelectric material because of its availability and much lower cost as compared to known thermoelectric materials. At the same time, the new material has shown high radiation resistance and stability of the parameters of heat energy converters made from it to high-intensity laser radiation. The ways of reducing the granular silicon resistivity have been discussed; the designs of thermal energy converters using natural or man-made heat, including concentrated solar radiation, as a heat source have been described.