Effect of Pulsed Photon Treatment on Electrophysical and Thermophysical Properties of n-Type Solid Solution Based on Bi_2Te_3-Bi_2Se_3:I. Electrophysical Properties

摘要

The effect of the pulsed photon treatment exerted on the electrical conductivity, the thermal EMF, and the power factor of n-type solid solution Bi_2Te_3-Bi_2Se_3 has been studied. The samples have been obtained by means of powder metallurgy in two stages consisting in the synthesis and hot pressing in an argon atmosphere. It has been found that the pulsed photon treatment in an argon atmosphere of samples synthesized by means of powder metallurgy leads to the surface layer recrystallization and to the changes in the phase composition owing to selenium sublimation. As a result of this, the concentration of free charge carriers in the material decreases, the thermal EMF exhibits an increase, and the electrical conductivity decreases. Depending on the pulse intensity, the mobility of free charge carriers can either decrease or increase. This makes it possible to choose a mode of pulsed photonic processing wherein the relative increase in the thermal EMF exceeds the decrease in the electrical conductivity of the material, as a result of which the power factor of the material exhibits a 2.6% increase.