Bylina I. Growth Processes, Morphology and Thermoelectric Properties of Thin Films Based on Lead Telluride.

Statistical processing of all nanoclusters on the surface of thin films using the watershed method is performed. The results of the calculation of the main structural characteristics are interpreted from the position of the Lifshitz-Slozov-Wagner theory, Ostwald ripening and the kinetic theory of thin film formation. As a result of the comparison of experimental data with theoretical calculations, the realization of two growth processes of thin films at the same time is established: diffusion and Wagner. Moreover, in the initial stages of condensation, the diffusion growth process is dominant, and it is responsible for the lateral growth of nanostructures on the surface. At later stages, there is an increase in the share of Wagner's growth process in the overall process of film formation. It is responsible for the growth of nanostructures in the normal direction. This statement is confirmed by a corresponding change in the shape factor of nanoclusters, which increases with increasing deposition time. The appearance of the bimodal distribution at a certain stage of deposition is explained by the implementation of the Ostwald ripening process. The dependence of azimuthal and polar angles of surface objects on the technological conditions of obtaining is established. It is determined that the substrate of sital does not give a certain orientation to nanocrystallites, unlike the substrate of mica, and on the surface of the samples objects are formed mainly by planes of cube and rhombic dodecahedron and their combinations. It is found that films obtained on mica substrates are characterized by higher thermoelectric power than films obtained on sital. The highest values of thermoelectric power are characteristic of films with a small thickness (in most cases 100 nm, but not more than 500 nm), obtained with a relatively short deposition time. A structural feature that provides high thermoelectric power in thin films is the small value of the shape factor, in which the average heights of surface nanoclusters do not exceed 10 nm, and their average diameters - 30 nm.