Thermoelectric materials based on cobalt-containing sintered silicon-germanium alloys

Abstract

Thermoelectric materials based on cobalt-containing SiGe alloy films were fabricated using monocrystalline silicon wafers with thin porous silicon layers electrochemically decorated with cobalt nanoparticles, filled germanium and subsequently subjected to rapid thermal processing. SEM, XRD, Raman spectroscopy and measurements of electrical conductivity and thermoelectric parameters revealed that an intermediate silicidization step involving thermal processing at 850 ◦C after cobalt deposition is crucial to maximize the resulting alloy’s thermoelectric capabilities. The obtained silicidized SiGe:Co samples demonstrate a Seebeck coefficient of -450 μV/K and an estimated figure-of-merit ZT value of up to 0.72 at 450 K due to the presence of crystalline cobalt silicides in the film. These results enable a new approach to the fabrication of thin film thermoelectric materials based on SiGe alloys.