Fizika Tverdogo Tela, 2024 Volume 66, Issue 11,Pages 1864–1870(Mi ftt10471)
Semiconductors
Study of the surface of nanocomposite thermoelectrics based on bismuth and antimony chalcogenides by scanning tunneling spectroscopy and atomic force microscopy
Abstract:
The surface morphology of nanocomposite solid solutions of Bi$_{0.45}$Sb$_{1.55}$Te$_{2.985}$ with SiO$_2$ microinclusions and nanostructured polycrystalline samples of Bi$_{0.45}$Sb$_{1.55}$Te$_{2.985}$ obtained by hot pressing was studied by atomic force microscopy (AFM) in semicontact mode. Optimization of the number, size of grains and nanofragments on the surface morphology images correlates with the thermoelectric properties, while in a nanocomposite with smaller grain sizes and nanofragments, the thermoelectric efficiency increases compared to polycrystal. The surface states of the Dirac fermions have been studied using scanning tunneling spectroscopy (STS). It is shown that the energy of the Dirac point ED, the surface concentration of fermions ns and the energy of surface levels formed by defects in pressed materials decrease compared to single crystals.
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