Growth and characterization of Ag–Al2O3 composites thin films for thermoelectric power generation applications

Abstract

Thin films of Ag–Al 2 O 3 composites were successfully grown on Si substrate by thermal evaporation method and their thermoelectric performance was modulated using post growth annealing technique. Pellet of Ag and Al mixture having 1:4 ratio was evaporated on Si substrate using the vacuum tube furnace. As grown sample was cut into pieces and post-growth annealing was performed at different temperatures using muffle furnace. XRD results suggested that as-deposited sample has amorphous nature, but crystallinity of the samples increase as an annealing temperature increase from 600 to 900 o C. This structural behavior of annealed samples was further verified by Raman spectroscopy measurements. We have reported an optimal annealing temperature (800 0 C) for the best thermoelectric performance of investigated composites. At this specific annealing temperature, charge carriers are highly mobile which resulted in the enhancement of thermoelectric power generation performance of Ag–Al 2 O 3 composite. The value of power factor (1.38x10 −2 W/m-K −2 ) reported in the current study is the highest value for Ag–Al 2 O 3 composites so for reported in the literature according to the best of our knowledge.