Electrical conductivity and thermoelectric power of (TlInSe2)0.2(TlGaTe2)0.8 crystals

The compounds TlInSe2 and TlGaTe2 have been prepared by direct elemental synthesis, and the (TlInSe2)(0.2)(TlGaTe2)(0.8) solid solution has been synthesized from them. Crystals of the (TlInSe2)(0.2)(TlGaTe2)(0.8) solid solution with a tetragonal structure have been grown, and their dc electrical conductivity and thermo-electric power have been measured in the temperature range 77-347 K. The results demonstrate that, at low temperatures, in the region of hopping conduction, the thermoelectric power of (TlInSe2)(0.2)(TlGaTe2)(0.8) is proportional to T. With increasing temperature, the thermoelectric power becomes inversely proportional to temperature when the conductivity begins to be dominated by charge carriers excited to the allowed band.