Investigation of structural, thermodynamic and energy state characteristics of the ZrNi1-xRhxSn solid solution

L.P. Romaka; Yu.V. Stadnyk; V.V. Romaka; P.-F. Rogl; V.A. Romaka; A.M. Horyn

doi:10.15330/pcss.19.2.151-158

Authors

L.P. Romaka Ivan Franko National University of Lviv
Yu.V. Stadnyk Ivan Franko National University of Lviv
V.V. Romaka Ivan Franko National University of Lviv
P.-F. Rogl Universitӓt Wien
V.A. Romaka National University “Lvivska Politechnika”
A.M. Horyn Ivan Franko National University of Lviv

DOI:

https://doi.org/10.15330/pcss.19.2.151-158

Keywords:

electrical conductivity, thermopower coefficient, Fermi level, electronic structure

Abstract

The peculiarities of crystal and electronic structures, thermodynamic and energy state characteristics of the ZrNi_1-_xRh_xSn semiconductive solid solution were investigated. It has been shown that in the ZrNiSn compound simultaneously exist two types of structural defects of the donor nature which generate two donor bands with different ionization energy in the band gap: a) the donor band ɛ_D¹, formed as a result of a partial, up to ~ 1%, occupation of 4a position of Zr atoms by Ni atoms (mechanism of “a priori doping”) and deep donor band ɛ_D², formed as a result of partial occupation of the tetrahedral voids by Ni atoms (Vac). The substitution in 4c position of the Ni atoms by Rh ones in ZrNi_1-_xRh_xSn generates structural defects of acceptor nature and creates an impurity acceptor band ɛ_A in the band gap, which, in addition to the existence of ɛ_D¹ та ɛ_D² donor bands, makes semiconductor highly doped and strongly compensated. The obtained results allow to understand the mechanisms of electrical conductivity of thermoelectric materials based on n-ZrNiSn and the ways of conscious optimization of their characteristics for obtaining the maximum efficiency of conversion of thermal energy into electric.

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