ICT2014 Abstracts

Present thermoelectric devices, either for cooling purposes or for generating electricity in small scale applications are still based on Bi-Te. This is because of the excellent thermoelectric performance, even for small temperature gradients and because of the lack of thermoelectric modules based on alternative materials like skutterudites or half-Heusler   alloys and produced on an industrial scale. The significant price of the Bi-Te based solutions, however, will avoid a mass market like that for recovery heat from the exhaustion pipe in combustions engines. Thus, new techniques and procedures, where only small quantities of the active thermoelectric elements are involved, are required.

The aim of the present work is to show that mesoscale Bi-Te films, produced on an industrial installation magnetron sputtering tool (Solaris from Oerlikon) with a high sputter rate, may be better suited with respect to costs in comparison with standard bulk p- and n-leg structures. We have prepared p- and n-type Bi-Te thin films on a metallized glass fibre enforced polyimide substrate (standard high-temperature pcb material from Arlon) with a thickness of about 50 µm and have carried out electron microscopy studies, x-ray diffraction as well as temperature dependent Seebeck coefficient and electrical resistivity measurements in order to derive the thermoelectric performance of these films. Employing a 3ω method allowed us to firstly derive the temperature dependent thermal conductivity of these industrially produced Bi-Te films. Here we also show, how structural features, like grain sizes, stoichiometry, etc. of these materials relate to its thermoelectric behaviour.

 The work leading to these results has received funding from the European Community's Seventh Framework Programme under grant agreement n° FP7–263306