Thermoelectric properties of P-type(Bi_(0.26)Sb_(o.74))2Te3+3Te ingots prepared by vacuum melting

摘要

P-type(Bi_(0.26)Sb_(0.74))2Te3+3%Te ingots were prepared by cooling at various cooling rates after vacuum melting .In this paper, the chemical composition, structure and thermoelectric properties of the crystals were evaluated by XRD, SEM, EDAX and thermoelectric measurements including Seebeck coefficient, electrical conductivity and thermal conductivity. With increase of cooling rates, Te-rich phase presents in the crystals, the electrical conductivity increases and the Seebeck coefficient decreases. While thermal conductivities of all ingots are all lower than 1.3W/mK. The maximum ZT (T=298K) was 1.12, which was obtained in the p-type(Bi_(0.26)Sb_(0.74))2Te3+3%Te ingot prepared at a cooling rate of 4K/min.