Comparative study of thermoelectric properties of Bi2Te3 and Bi95Sb5 of varying crystalline size and disorder

Abstract

Measurements of Hall effect, conductivity, and thermoelectric figure of merit $\text{L}$ were made over the temperature range 77–300°K on Bi₂Te₃ samples which had been sintered for 1, 5, and 30 hr, and on a Bi₂Te₃ single crystal which had been prepared by the Bridgman method. Conductivity, magneto-resistance and $\text{L}$ were also measured over the same temperature range on Bi₉₅Sb₅ samples qhich had been sintered for 5 and $\text{10}\text{1}\text{4}$ hr. The latter results were compared with data reported by Smith and Wolfe [4] for a Bi₉₅Sb₅ single crystal. In all cases, $\text{L}$ was lower for the sintered samples than for the corresponding single crystals. Over the above temperature range, the $\text{L}$ of the best sintered specimen of Bi₂Te₃ varied from 0 · 5 × 10⁻³/°K to 1 × 10⁻³/°K, and the $\text{L}$ of the sintered damples of Bi₉₅Sb₅ ranged from 1 · 38 × 10⁻³/°K to 0 · 52 × 10⁻³/°K.