Gallium antimonide-doped germanium clathrate - A p-type thermoelectric cage structure

A germanium clathrate compound doped with gallium antimonide has been synth esized and characterized, The structure of Ba8Ga16(GaSb)(x)Ge30-2x with x = 2 was determined using single-crystal X-ray analysis, and the Sb atoms wer e found to be selectively sited. A slight excess of antimony was confirmed by microprobe elemental analysis, resulting in uncompensated doping of the framework. A positive and relatively high Seebeck coefficient of 100 mu V/K indicates this compound is a potential p-type thermoelectric material. Sin gle-crystal temperature-dependent conductivity indicates that the sample be haves as a poor metal. This is the first example of p-doping reported for c lathrates. (C) 2000 Academic Press.