Characteristics of Bi0.5Sb1.5Te3/Be2Te2.4Se0.6 thin-film thermoelectric devices for power generation

The characteristics of flash-deposited Bi2Te2.4Se0.6 and Bi0.5Sb1.5Te3 thin-film thermoelectric generators are described. The overall Seebeck coefficient for a single couple in the generator (Bi2Te2.4Se0.6 forming the n-type thermoelement and Bi0.5Se1.5Te3 forming the p-type element) is 410 mu V K-1. This value approaches the figures presented for these materials in bulk form. The results demonstrate how the parameters of the generator can be altered in order to maximize generation efficiency. For example, doubling the cross sectional area of the thermoelement can result in a two-fold increase in the output power. Extrapolation of the results indicates that a generator of dimensions 0.5 cm x 0.7 cm x 0.015 cm can provide a voltage source sufficiently powerful to drive a microelectronic circuit (namely 3-5 V at about 10 mu A). Hence, potentially, the generator could be used in place of a battery unit in small-scale generation applications, where a source of waste heat is available.