Effect of annealing on the structural and thermoelectric properties of nanostructured Sb2Te3/Au semiconductor/metal multilayer films

This paper investigates the influence of thermal annealing temperature on the periodic nanostructures and the thermoelectric properties of Sb2Te3/Au multilayer thin films fabricated by magnetron sputtering. The as-deposited amorphous periodic multilayer films (10 periods, 20 and 7 nm for the Sb2Te3 and Au layers, respectively) show regular and sharp interfaces between Sb2Te3 and Au layers. It was found that the interfaces of periodic films became a little fuzzy and some nanocrystallines could be observed after annealing at relatively lower temperature (373 K) due to atomic diffusion and crystallization. Additionally, obvious crystal grains appeared and the Au layers began to coarsen and even rupture when the annealing temperature was elevated to higher than 423 K. The evolution mechanism has been discussed in the view of grain boundary free energy and interfacial free energy. Furthermore, the experimental results suggest that the resistivity and Seebeck coefficient of the multilayer film sample have not exhibited distinct change until the annealing temperature was increased to as high as 473 K when the periodic nanostructures disappeared. (C) 2019 Elsevier B.V. All rights reserved.