Effect of Photon Treatment on the Structure and Electrical Properties of n-Type Bi_2Te3-Bi_2Se3 Solid Solution

摘要

The effect of pulsed photon treatment on the electrical conductivity, thermopower and power factor of the ntype solid solution Bi_2Te_3 - Bi_2Se_3 has been investigated. Samples obtained by powder metallurgy method, which includes two main stages - synthesis, hot pressing in an argon atmosphere. It was established that pulsed photon treatment of samples in an argon atmosphere leads to recrystallization of the surface layer and a change in the phase composition due to the diffusion of Te from the volume to the surface. As a result, the concentration of free charge carriers in the material decreases. This leads to an increase in thermopower and a decrease in electrical conductivity. At the same time the mobility of free charge carriers can both decrease and increase depending on the pulse intensity. This feature made it possible to choose the mode of pulsed photon treatment, in which the relative increase in thermopower exceeded the decrease in the electrical conductivity of the material. This led to an increase in the power factor of the material by 2.6%.