Transport coefficients of titanium-doped Sb/sub 2/Te/sub 3/ crystals

Titanium-doped single crystals (c/sub Ti/ = 0 to 2/spl times/10/sup 20/ atoms cm/sup -3/) were prepared from the elements Sb, Ti, and Te of 5N purity by a modified Bridgman method. The obtained crystals were characterized by measurements of the temperature dependence of the electrical resistivity, Hall coefficient, Seebeck coefficient and thermal conductivity in the temperature range of 5-300 K. It was observed that with an increasing Ti content in the samples the electrical resistance, the Hall coefficient and the Seebeck coefficient increase. This means that the incorporation of Ti atoms into the Sb/sub 2/Te/sub 3/ crystal structure results in a decrease in the concentration of holes in the doped crystals. For the explanation of the observed effect a model of defects in the crystals is proposed.