Electrical and thermoelectric properties of SbI3-doped 25% Bi2Te3-75% Sb2Te3 and 15% Bi2Te3-85% Sb2Te3 single crystals

摘要

The temperature dependences of the electrical andthermoelectric properties of the SbI3-doped 25% Bi2Te3-75%Sb2Te3 and 15% Bi2Te3-85% Sb2Te3 single crystals, grown by theBridgman method, were measured at temperatures ranging from77 K to 600 K For the Sb2Te3-rich single crystals, the temperaturedependence of the Hall mobility was T-1.0 regardless the Sb2Te3contents and added amount of SbI3. The temperature dependencesof (m*/m0)3/2 μc and effective mass m*/mo were T1.5 and T-1/3,respectively. The decrease of the saturated hole concentration andthe change of the slope of the Seebeck coefficient with temperaturewere considered in the view point of the two sub-bands in thevalence 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 and1.95×10-3/K, respectively.