  Hot wall technique was used to grow block single crystal films of Bi_2Te_3
and solid solutions of Bi_(0.5)Sb_(1.5)Te_3 on mica (muscovite) substrates.
X-ray diffraction studies demonstrated that the crystalline c-axis in the films
was normal to the substrate plane. Seebeck coefficient, electrical conductivity
and magnetoresistivity tensor components were measured at various orientations
of magnetic and electric fields in the temperature interval 77-300 K and
magnetic field up to 14 T. Scattering mechanism of charge carriers in the films
were studied using temperature dependences of the degeneracy parameter and the
Seebeck coefficient in terms of a many-valley model of energy spectrum.
Obtained results have shown that the effective scattering parameter is
considerably differed from the value specific for an acoustic scattering of
charge carriers in the weakly degenerate films due to an additional scattering
of charge carriers on interface and interctystallite boundaries. These features
of charge carrier scattering are supposed to affect electronic transport in the
films and enhance figure of merit.
