Charge transfer processes in granulated Mg3Sb2 particles

Abstract

In the article, temperature dependence of specific resistance (ρ), concentration of charge carriers (n) and mobility (<) was studied experimentally at T=300-700 K to study charge transfer processes in granulated Mg3Sb2 particles. The research results were explained on the basis of the charge transfer mechanism in Mg3Sb2 particles. In particular, at the initial stage of temperature increase, Т≤375 К, localized traps with energy level Ein appear in the interparticle boundary areas of the heated part of the sample. When charge carriers are trapped in them, ρ increases sharply, and n decreases. In the later stages of temperature increase, the thermal phenomenon increases along the length of the sample. In this process, localized traps with energy level Ein appear successively in the interparticle boundary regions located along the length of the sample. In relation to the charges held in them, the concentration of the generated charge carriers n increases in accordance with the increase in temperature, in this case ρ changes steadily. The increase of the potential barrier height in the interparticle boundary regions from φ ~ 0.411 eV to 0.91 eV confirms the above considerations. In addition, under the influence of temperature, the particle size and impurity ionization in the interparticle boundary areas or thermal fluctuations of the crystal lattice decrease the free movement path of the carriers. This leads to a decrease in µ at T=300-700 K.