Study of the n-type Bi2Te2.7Se0.3 doped with bromine impurity

Solid solutions with the composition of Bi2Te2.7Se0.3, whether doped with bromine impurity or not, have been grown using the Bridgman method. Structural and thermoelectric characterizations of samples cut along the as-grown ingots of these solid solutions are carried out. With the help of electrical and ther mal conductivities and the Seebeck coefficient at room temperature, the point defects responsible of the p-type conductivity in non-doped solid solutions are discussed. The analysis of the experimental results concerning the doped solution with bromine atoms leads to obtain the segregation coefficient of Br nearly equal to one. The electrical activity of this impurity is discussed when substituted for Te and when an atom of bromine may be a single donor. (C) 2000 Elsevier Science Ltd. All rights reserved.