Flash evaporated layers of (Bi 2Te 3–Bi 2Se 3)(N) and (Bi 2Te 3–Sb 2Te 3)(P)

Abstract

(Bi 2Te 3) 0.9(Bi 2Se 3) 0.1 for N-type material powder and (Bi 2Te 3) 0.25(Sb 2Te 3) 0.75 for P-type material powder were evaporated by a flash evaporation technique. We obtained a value of Z equal to 0.21×10 −4 K −1 for α=40 μV K −1 and ρ=50 μΩ·m for P-type material and Z of about 0.17×10 −3 K −1 for α=90 μV K −1 and ρ=30 μΩ·m for N-type material (at 300 K), for 1 μm layer thickness deposited over polyimide substrate, before annealing. We show that after annealing at 250°C under He atmosphere, the figure of merit of the layers increases to Z=3.2×10 −3 K −1 for α=240 μV K −1 and ρ=12 μΩ·m for P-type material and Z=1.6×10 −3K −1 for α=200 μV K −1 and ρ=15 μΩ·m for N-type material (at 300 K). With these fabrication parameters, we realised three different structures of micromodule Peltier (MMP) junction and we obtained a maximum value for temperature drop between hot and cold sides of ≈3.4 K. This result is very promising in order to develop MMP.