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Abstract:
Polycrystalline samples of Cu3-xSnxSe3 were synthesized in the
composition range x = 0.87-1.05. A compositionally induced evolvement
from tetragonal via cubic to monoclinic crystal structures is observed,
when the composition changes from a Cu-rich to a Sn-rich one. The
Cu3-xSnxSe3 materials show a metal-to-semiconductor transition with
increasing x. Electronic transport properties are governed by the
charge-carrier concentration which is well described by a linear
dispersion-band model. The lattice component of the thermal conductivity
is practically independent of x which is attributed to the opposite
influence of the atomic ordering and the inhomogeneous distribution of
the Cu-Se or Sn-Se bonds with different polarities in the crystal
structure. The highest thermoelectric figure of merit ZT of 0.34 is
achieved for x = 1.025 at 700 K.
