INVESTIGATION OF KINETIC CHARACTERISTICS OF SENSITIVE ELEMENTS OF THERMOCONVERTERS BASED ON Ti1-xMoxCoSb

Mathematical modeling and experimental measurements of the kinetic and energy characteristics of the sensitive elements of thermo converters based on the thermometric material Ti1-xMoxCoSb in the temperature range 80-400 K was carried out. Previous studies of the electrophysical, energetic, and structural properties of thermometric materials obtained by doping the TiCoSb  semi-Heisler phase with Ni and V  atoms  respectively have  shown  that  they  are  inherent  in  the  stable  and  reproducible characteristics at 4.2–1000 K. It was revealed that the results of modeling the thermometric characteristics of the sensitive elements based on TiCo1-xNixSb and Ti1-xVxCoSb did not agree with  the experimental results. This made  impossible  to use the mentioned materials  for  the manufacturing  the  sensitive  elements  of  resistance  thermometers  and  thermoelectric  transducers. Modeling  of Electronic Structure of Ti1-xMoxCoSb Thermometric Material with help of The Korringa–Kohn–Rostoker (KKR) Green Function Method in Coherent Potential Approximation and Local Density Approximation using AkaiKKR and SPR-KKR Software of the exchange-correlation potential with the parameterization of Moruzzi-Janak-Williams have envisaged that the substitution of Ti at Mo generates structural defects of the donor nature in the crystal (Mo has more 3d electrons than in Ti), and in the bandgap near the  conduction  band  εC  impurity  donor  level  (zone) ε2D.  Measurements  of  the  electrokinetic  characteristics  of  Ti1-xMoxCoSb thermometric  materials  determined  the  presence  of  high-temperature  activation  sites  on  the  specific  resistance  of  ln(ρ(1/T)), indicating the location of the Fermi level εF in the Forbidden Zone of a Semiconductor, which is possible under the condition of generating acceptors that capture free electrons, reducing their concentration, and slowing the movement of the Fermi level to the level of the conductivity zone. Thus, doping the TiCoSb compound with the Mo admixture produces the generation of structural defects  of  the  acceptor  and donor  natures  in  the  crystal. Mechanisms  of  electrical  conductivity  of  sensing  elements  of  thermoconverters are established.