Electrical and Thermoelectric Properties of SbI3 - doped 25% Bi2Te3-75% Sb2Te3 and 15% Bi2Te3-85% sb2Te3 Single Crystals
현도빈D . B . Hyun,하헌필H . P . Ha,심재동J . D . Shim,황종승J . S . Hwang,오태성T . S . Oh
Abstract
The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 15% Bi₂Te₃-85% Sb₂Te₃ single crystals, grown by the Bridgman method, were measured at temperatures ranging from 77 K to 600 K. For the Sb₂Te₃-rich single crystals, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents and added amount of SbI₃. The temperature dependences of (m*/m_o)^(3/2)·μ_c and effective mass m*/m_o were T^(-1.5) and T^(-1/3), respectively. The decrease of the saturated hole concentration and the change of the slope of the Seebeck coefficient with temperature were considered in the view point of the two sub-bands in the valence band. The maximum figure-of-merit at 300 K of 0.2 wt% SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 0.4 wt% SbI₃-doped 15% Bi₂Te₃-85% Sb₂Te₃ single crystals were 2.25×10^(-3)/K and 1.95×10^(-3)/K, respectively.