Physico-Chemical Bases Cultivation Variable-gap Semiconductor Solid Solution Si1−xGex from the Liquid Phase

Single-crystal films of a graded-gap solid solution Si1-xGex (0 <x <1) was grown on Si substrates from limited tin, gallium solution-melt. Accordingly, liquid phase epitaxy method was applied in the process. The formation of dislocations, grown under various technological conditions, at the substrate-film interface along the growth direction of the Si1-xGex solid solution was studied. Optimal technological growth modes for obtaining crystalline perfect epitaxial layers and structures are given.

Photon treatment effect on the surface and figure of merit of thermoelectric material Bi2Te3−xSex

The phase composition, structure, morphology, and thermal conductivity of Bi2Te3−xSex-based semiconductor solid solution after photon treatment (PT) were studied by X-ray diffractometry, SEM, TEM, and the laser flash techniques. It was revealed that PT leads to recrystallization of the subsurface layers of the solid solution with the formation of a heterogeneous nanocrystalline structure. The thermoelectric figure of merit of the semiconductor Bi2Te3−xSex (n-type) solid solution increases after PT due to modification of the surface layers. This is due to the decrease of the thermal conductivity of the studied material after PT.

Investigation of Band Structure of ZrNiSn1-xGax Semiconductor Solid Solution

The mechanism of simultaneous generation of donor-acceptor pairs in ZrNiSn1-xGax semiconductor solid solution is established. The modeled distribution of atoms in the crystal lattice of ZrNiSn1-xGax showed that the speed of movement of Fermi level εF, obtained from the band structure calculations is in agreement with experimental extracted from lnρ(1/T) dependencies. It is shown that with substitution of Sn (5s25p2) with Ga (4s24p1) atoms in 4b crystallographic site both acceptor and donor (vacancies in 4b site) defects are generated.

Investigation of Crystal and Electronic Structures Features of Hf1-xTmxNiSn Semiconductor Solid Solution

The features of structural, energy state and electrokinetic characteristics were investigated for Hf1‑xTmxNiSn solid solution in the range: T = 80 - 400 K, x = 0 - 0.40. It was confirmed partly disorder crystal structure of HfNiSn compound as a result of occupation in the 4a crystallographic site of Hf (5d26s2) atoms by Ni (3d84s2) ones up to ~ 1 % that generates in the crystal structural defects of donor nature. It was shown that introduction of Tm atoms ordered crystal structure (“healing” of structural defects). It was established mechanisms of simultaneous generation of structural defects as acceptors by substitution of Hf (5d26s2) by Tm (4f135d06s2) atoms, and the donor nature defects as a result of the appearance of vacancies in the Sn (4b) atoms sites, which determines the mechanisms of conductivity for Hf1-xTmxNiSn.