Kostiuk O. Classical and quantum size effects in transport phenomena in thin films of solid solutions PbSnAgTe

On the basis of complex experimental studies and theoretical calculations, the effect of classical and quantum size effects on the thickness dependence of the thermoelectric parameters of thin films on the base of n-PbTe and PbSnAgTe has been investigated.The dependence of thermoelectric properties on thickness and temperature for thin films on the basis of Pb14Sn4Ag2Te20, Pb16Sn2Ag2Te20 and Pb18Ag2Te20 compounds obtained on mica substrates has been investigated. It is shown that the films based on Pb14Sn4Ag2Te20 compounds have the highest thermoelectric power S2σ in comparison with other studied compositions.The influence of surface scattering on the electrophysical properties of PbTe is considered on the base of models of quasiclassical approximation and Fuchs- Sondheimer. The influence of diffuse and specular scattering mechanisms on the interphase boundaries, as well as the scattering of charge carriers on the grain boundaries, is determined. The mechanisms of current transfer between grain boundaries related to thermionic emission are also considered.The experimental dependences of the magnetoresistance of PbSnAgTe films on the composition and on the temperature in the perpendicular to the surface of the film magnetic field are obtained. Their explanations are analyzed on the base of the theory of quantum corrections to conductivity associated with weak localization and spin-orbit interaction.Theoretical and experimental oscillations have been obtained in the profiles of thermoelectric coefficients of nanostructures based on Pbm-x-2SnxAg2Tem. The possibility of realizing the quantum dimensional effect in thin films of Pbm-x-2SnxAg2Tem is explained in detail. It is also shown that the obtaining of low-dimensional condensates allows improving the thermoelectric properties of the material