Optimized thermoelectric performance in thin (Bi2Se3)1−x(Bi2Te3)x alloyed films

Abstract Herein, thin films of (Bi2Se3)1-x(Bi2Te3)x were synthesized by thermal evaporation in high vacuum using highly crystalline bulk samples of Bi2Se3 alloyed with Bi2Te3. Preparation and characterization together with probing the thermoelectric properties of thin (Bi2Se3)1-x(Bi2Te3)x films are discussed in this article. Crystal structure, surface morphology, roughness and lattice features of the deposited films were probed via XRD, SEM and HRTEM techniques, which confirmed the perfect crystallinity and the nano-scalability of the prepared thin films. Thermoelectric measurements were carried out for the as-deposited films within a temperature range of 300-473 K. Seebeck coefficient of the studied samples is about two times larger than that of the previously reported bulk samples. The highest power factor was recorded at 131 μW/mK2 and 473 K. The high value of the power factor shows that the materials under the study are promising for applications such as resource recovery of waste and also as nanomaterials for environmental applications. Very low electronic thermal conductivity was obtained due to the small electrical conductivity and due to the scattering of carriers by the tiny grains constituting the prepared films.