Optimization of hot-pressed n-type SbI/sub 3/-doped Bi/sub 2/Te/sub 2.85/Se/sub 0.15/ compounds

The n-type SbI/sub 3/-doped Bi/sub 2/Te/sub 2.85/Se/sub 0.15/ thermoelectric compounds were fabricated by the hot pressing in the temperature range of 380 to 420/spl deg/C under 100, 150 and 200 MPa in Ar. The transmission electron microscopy, and X-ray diffraction were used to investigate the detailed microstructure. We fabricated relatively dense compounds. The relative density of the compounds fabricated at 420/spl deg/C was 99.6%. The grains of the compounds were preferentially oriented along the perpendicular to the pressing direction through the hot pressing and also the degree of preferred orientation increased with the hot pressing temperature and pressure. In addition, with increasing the hot pressing temperature, the figure of merit was increased due to the increase in density and preferred orientation. The highest figure of merit (2.35/spl times/10/sup -3//K) was obtained at 420/spl deg/C under 200MPa.