Electric and thermoelectric properties of CdTe/PbTe epitaxial nanocomposite

The electric and thermoelectric properties of novel, CdTe/PbTe layered nanocomposite material are investigated. The molecular beam epitaxy (MBE) method was used for preparation of samples with well controlled distances (from 20 to 70 nm) between the layers of CdTe nanograins embedded in PbTe thermoelectric matrix as well as with number of these layers from 2 to 10. The Hall effect measurements performed in temperature range from 4-300K revealed that carrier mobility is strongly affected by scattering on CdTe grain boundaries. The observation of Shubnikov-de Haas oscillations confirms high quality of the samples and allows determination of effective mass of conducting electrons m* = 0.04m(0). The measurements of the room temperature Seebeck coefficient together with electrical conductivity lead to the power factors which are comparable to those reported in PbTe/CdTe polycrystalline solid solutions.