Thermoelectric properties of tetradymite-like layered materials in the pseudoternary system Sb2Te3–GeTe–Bi2Te3

Resumo

The Hall coefficient, resistivity, and thermoelectric power of quaternary tetradymite-like layered materials in the pseudoternary system Sb₂Te₃–GeTe–Bi₂Te₃ have been measured in the temperature range 100–800 K. The results demonstrate that all of the samples studied in the Sb₂Te₃–GeTe–Bi₂Te₃ system are p-type and have high hole concentration due to point defects. Plots of lnσ against 1/T in the intrinsic region were used to evaluate the band gap (ΔE) of two materials: GeSb_3.91Bi_0.03Te_6.91(ΔE = 0.22 eV) and GeSbBiTe₄ (ΔE = 0.197 eV).