We have studied the effect of doping with Sn (0.004 and 0.008 at %) on the properties of Bridgman-grown single crystals of an n-type Bi2Te1.5Se1.5 solid solution. Thermoelectric power, electrical conductivity, thermal conductivity, and Hall effect measurements in the range 77–400 K have shown that Sn influences the electrical transport properties of the solid solution. Single crystals with the composition Bi1.9996Sn0.0004Te1.5Se1.5 have higher thermoelectric efficiency in the temperature range 300–370 K than does the Sn-free solid solution. Moreover, measurements of thermoelectric power, which is rather sensitive to carrier concentration fluctuations, have demonstrated that the Sn-doped single crystals have highly uniform electrical properties along their length and across this direction.
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