J.W. Sharp

The semiconductor alloy system (GeTe)_1-x(AgSbTe₂)_x, known as TAGS, is a family of highly degenerate p-type materials with peak ZT well above room temperature. For instance, when x = 0.15, ZT is about 1.4 at 773 K, but is only ~0.2 at 300 K with a Seebeck coefficient less than 100 mV/K. We revisit this familiar material and some related alloys with regard to their potential for operation at lower temperatures. We are exploring alternative compositions and processing that provide the same or similar crystal structure, in an effort to improve the room-temperature electrical properties and, consequently, the figure of merit.