2018 年 30 巻
We investigated the structual and thermoelectric properties of electrodeposited Bi2Te3 thin films using a two-step process which combined an homogeneous electron beam irradiation with a thermal annealing. The Bi2Te3 thin films were formed on stainless steel substrates by the potentiostatic electrodeposition. We first performed only the thermal annealing to the thin films to determine the optimal annealing temperarure. As a result, we found that the Bi2Te3 thin films at the annealing temperautre of 300°C exhibited the highest thermoelectric performance, which was 4.5 times higher than that of the as-deposited thin films. Thus, in the two-step process, the electron beam irradiation dose was changed from 0.36 to 1.08 MGy while the annealing temperature was set at 300°C. As a result, the Bi2Te3 thin films at the EB irradiation dose of 0.36 MGy exhibited highest thermoelectric properties [power factor = 6.1 μW/(cm·K2)] which was approximately 20% higher than that of the optimized thin films with only the annealing treatment. Therefore, we conclude that two-step process is beneficial to improve the thermoelectric properties of electrodeposited Bi2Te3 thin films.