The research of temperature dependences of electrical conductivity and thermopower of WS$_2$ and WSe$_2$ with partial replacement of W on Nb

The temperature dependences of electrical conductivity and thermopower of tungsten disulfide and tungsten diselenide have been investigated in this paper. These materials have the low value of electrical conductivity. The main idea of this paper is the increase of electrical conductivity for obtaining high thermoelectric efficiency. Niobium have served as an acceptor impurity. It has been revealed that the replacements of metal atoms have increased of electrical conductivity of W$_{0.85}$Nb$_{0.15}$Se$_2$ by $4$ order of magnitude. While the thermopower has decreased with increasing of impurity concentration. The thermoelectric power factor has been calculated for materials. The figure of merit $ZT$ of the best composition W$_{0.95}$Nb$_{0.05}$Se$_2$ has been estimated and has had a value of 0.02 at room temperature.