Effect of Pulsed Photon Treatment on the Mechanical Properties of Semiconductor Thermoelectric Legs, Based on Bi2Te3–Bi2Se3 Solid Solutions, and the Adhesion of Switching Layers

Photon treatment effect on the surface and figure of merit of thermoelectric material Bi2Te3−xSex

“…The change in the elemental composition is caused by diffusion triggered by the high temperature at the sample surface and occurring during the PT process [19]. Some authors found that Te sublimation occurs in the PT process, leading to the formation of various defects (vacancies, nanopores) [20]. Figure 6 shows the thermal conductivity as a function of temperature for the studied samples.…”

“…Thus, the fraction of grain boundaries in the bulk of the semiconductor differs by 30-40 times relative to that near the surface. It was reported [20,25] that an increase in ZT in the nanostructured thermoelectric materials is originated from the decrease in the thermal conductivity caused by the phonon scattering on the nanosized inhomogeneities. In our case, the grain boundaries act as such inhomogeneities, occurring due to the segregation of impurity atoms and selenium that diffuses in the PT process.…”

“…As shown in [19], the mechanical polishing followed by the photon treatment (PT) through the irradiation of semiconductor surfaces by the powerful xenon lamps increases the adhesion of a contact metallization to the semiconductor branches. PT initiates the recrystallization processes, which leads to the formation of a nanocrystalline structure in the subsurface layers of semiconductors [20]. It was shown that the formation of 15-20-nm-thick nanoplates (defects) in the Sb 2−x Bi x Te 3 structure is accompanied by a 15% increase in ZT, compared to the "standard" material [21].…”