Silicide Thermoelectrics: Materials for Energy Harvesting

The silicide family of thermoelectrics includes more than 15 compounds, among them are semimetals and semiconductors with band gaps ranging from 0.1 to 2.3eV. The silicides have obvious attractive features as the materials for thermoelectric energy converters. Many of the constituting elements are abundant, have low price, the compounds have good high temperature stability. Another feature of silicides, much less recognized by thermoelectric community, is their compatibility with silicon-based microelectronic technology. It opens a door for development of integrated thermoelectric power sources (energy harvesters) for electronic circuitry of wireless sensors and actuators. Considerable efforts have been undertaken, especially in the past 10 years, in order to develop efficient silicide-based thermoelectric materials. Currently the most efficient silicide thermoelectrics are based on Mg-2(Si-Sn) alloys, MnSi1.75 and ReSi1.75. This article is a review of the current status of the research on the silicide-based thermoelectric materials. Most of the non-transition metal silicides were intentionally excluded from this review. On the other hand more attention is paid to the silicide materials, which have been not in the research focus; to compounds with topologically non-trivial electronic structure, such as CoSi and SrSi2.