Iron disilicide as a thermoelectric generator material

The properties of iron disilicide (FeSi2) have been investigated, and it has been shown to be a semiconductor with a thermal energy gap of 0.88 ± 0.04 eV. It has been found possible to dope FeSi2 both n and p type by the substitution of suitable elements for iron and silicon. The doping mechanism is obscure since relatively gross quantities (2¿5%) of dope are required to achieve optimum thermoelectric properties. Substitution of cobalt for iron yields an n-type material, and substitution of aluminium for silicon produces a p-type material. These materials have Z > 2 × 10¿4 deg C¿1 over the temperature range 150¿650°C. The materials are oxidation-resistant, thermally stable and mechanically strong. A method of construction is described which exploits the properties of these materials and should produce a cheap, robust generator of high power/weight ratio.