Electrical properties of Bi-2-xSbxTe3 materials obtained by ultrarapid quenching

Bismuth and antimony telluride alloys were prepared using the ultrarapid qu enching process route. The electrical properties of these materials were th en characterized by measuring the Seebeck coefficient, Hall coefficient and electrical resistivity. It appeared that the Bi2-xSbxTe3 materials changed from the n-type to the p-type at an x-value of about 0.7. For n-type mater ials, the Bi1.6Sb10.4Te3 foils (x=0.4) showed a maximal Seebeck coefficient with a value of -100 muV K-1. For p-type materials, a maximal Seebeck coef ficient was observed for x-values varying from 1.2 to 1.6 with a value of 1 35 muV K-1. The evolutions of the Seebeck coefficient, electrical resistivi ty, Hall coefficient with temperature, from 77 to 300 K, showed the degener ate nature of the quenched materials. The evolution of the mobility with te mperature indicated that the diffusion mechanism was mainly associated with acoustic phonon scattering. The study evidenced that the Bi,,,,Sb,,,,Te, a lloy has optimal electrical properties with a carrier concentration of 3.2X 10(19) cm(-3), a Hall mobility of 150 cm(2) V-1 s(-1) and a Seebeck coeffic ient of 225 muV.K-1 after annealing. (C) 2001 Elsevier Science B.V. All rig hts reserved.