Crystallization Process of Sputtered Co/Sb Multi-Layered Films with AlN Capped Layer during Annealing and their Thermoelectric Properties
Year: 2003
Type: article
Abstract: In order to investigate thermoelectric properties of Co-Sb binary films with a wide deposited composition range from 50 to 80 at%Sb, Co/Sb multi-layered films with AlN capped layer are synthesized by rf sputtering method. As-deposited films are annealed at 773 K for 1 h in a vacuum atmosphere. Transmission electron microscopy observation reveals the evolution of CoSb-β phase, CoSb2-γ phase and CoSb3-δ phase at elevating temperature, which corresponds to the variations of electrical resistance. Annealed films reproduce the phases expected from the equilibrium phase diagram. It is confirmed that the AlN capped layer is effective to suppress the sublimation of Sb and the occurrence of intergranular fracture, which leads to increase in the resistivity. Temperature dependence of Seebeck coefficients of annealed film is also measured. Because of large resistivity, the power factor of films with deposited composition of 75-80 at%Sb, which contains mainly CoSb3 phase, is smaller than the reported values. However, the film with deposited composition of 60%Sb, which contains mainly CoSb2 phase, shows large power factor, which is larger than the values reported for CoSb3 at more than 600 K. Then it is found that the CoCb2 is also promising thermoelectric material with n-type.
Authors: Shunsuke Maruyama, Takashi Ishiguro
Institution: Nagaoka University of Technology
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2606308255