Silver and copper halide doped bi2te3-as2se3 thermoelectric material

摘要

A semi-conducting alloy consists of a solid solution of Bi2Te3 and As2Se3 and a doping additive in a quantity sufficient to enhance the n-conducting properties of the basic material, the additive being a halide of a Group Ib metal. Examples of good additives are copper bromide and silver iodide, respectively used in quantities of 0.05-0.07 wt. per cent and about 0.1 wt. per cent of the composition. In the preferred materials the mol. ratio of Bi2Te3 to As2Se3 is between 7 : 3 and 9 : 1. Two examples are outlined. In one, the four main elements are fused together with copper bromide in an evacuated quartz tube and lowered slowly through a furnace at 600 DEG C. to eventually form a polycrystalline rod. In the second example the main elements are fused with silver iodide in an evacuated quartz tube within which the material is subsequently reverse-pass zone refined.