3rd TAGRA

Bismuth telluride is a layered crystal with unique properties utilized in thermoelectrics and various sensors; it is a topological insulator and a promising material for spintronics. Of practical interest is the type of transport that achieves the maximum charge transfer density with maximum phonon scattering, which makes it possible to increase the thermoelectric figure of merit of the material by reducing thermal conductivity. It is known that in layered crystals, a portion of the super-stoichiometric excess and impurities forms nanostructural elements within interlayer spaces and defect cavities; in our case, the formation of nanocomposites in the form of superstructures was observed in doped Bi2Te3. The diverse nature of charge transport in a crystal—composed of phases with differing conduction characteristics and featuring an ordered structure of quintet-block arrays interspersed with layers of nano-inclusions and islands—significantly influences overall charge transport; this process is governed by the interplay between the crystal's continuous energy spectrum and the energy spectra and wave functions of localized states, the distribution of electron density across the material's thickness, band discontinuities at interfaces, and the rates of charge carrier emission and trapping at localized levels. Structural arrangement features significantly influence the mechanical properties of the crystals—a factor crucial for producing strengthened materials intended for use under high mechanical loads. We obtained strengthened Bi2Te3 crystals doped with various impurities (Cu; Cu+In; Ni; Fe, B, Zn) that exhibited a 15% increase in thermoelectric efficiency.