Electron beam co-deposited Bi1−xTex

Abstract

Bi_1−xTe_x-compounds are among the most commonly used thermoelectric materials due to their high Seebeck coefficient, high electrical conductivity and low thermal conductivity at room temperature. N-type Bi_1−xTe_x-thin films for thermoelectric applications were deposited onto glass substrates by electron beam co-evaporation. The thin films cover the range of x = 0.57–0.66. In this study, the influence of the stoichiometry on the Seebeck coefficient, electrical conductivity and the derived power factor for as-deposited thin films is investigated. The results show a maximum power factor of 310 μW m⁻¹ K⁻² for x = 0.59. All samples were annealed to a maximum temperature of 350 °C in steps of 50 °C for 10 h each and the thermoelectric properties were measured after each annealing step. A significant improvement for the thermoelectric properties of the samples was achieved with thermal annealing at 300 °C resulting in a maximum power factor of about 1800 μW m⁻¹ K⁻².