Electric and Thermoelectric Characteristics of Sb/Te and Te/Sb Bilayer Thin Films Comprising Single-Phase Sb and Te Thin Films at Room Temperature

Abstract

We report on the electric and thermoelectric properties of 200-nm-thick Sb/Te and Te/Sb bilayer thin films that are deposited in sequence on SiO2/Si substrates by electron beam evaporation at room temperature. In addition, the sequentially deposited bilayer films were converted into Sb2Te3 alloys by a post-annealing process at 320 degrees C. We found that the average resistivity and thermal conductivity of both the bilayers increased from similar to 2.3 x 10(-4) to similar to 5.5 x 10(-4) Omega.cm and from similar to 0.5 to similar to 0.9 W/m.K, respectively, after the thermal annealing process. We suggest that this increase in thermal conductivity of the annealed bilayer films can be explained by the enhancement in the phonon boundary scattering due to the increase in the grain size after annealing. For comparison, we also prepared single-phase Sb and Te films with a thickness of 200 nm by e-beam evaporation. The influence of the bilayer on the microstructure and the electrical and thermoelectric properties of the samples are discussed.