Powder Aerosol Deposition of Bi2Te3: Thermoelectric Properties from Thick Films to Bulk Like Samples

Titelangaben

Schönauer-Kamin, Daniela ; Paulus, Daniel ; Kita, Jaroslaw ; Moos, Ralf:
Powder Aerosol Deposition of Bi2Te3: Thermoelectric Properties from Thick Films to Bulk Like Samples.
2026
Veranstaltung: European Conference on Thermoelectrics (ECT26) , 14th - 18th September 2026 , Edinburgh, United Kingdom.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Vortrag )

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Abstract

Bismuth telluride (Bi₂Te₃) is one of the most relevant thermoelectric materials for room temperature applications, making scalable, flexible, and cost efficient fabrication routes highly attractive. Powder aerosol deposition (PAD) is a room temperature fabrication method that enables the rapid processing of thermoelectric materials such as Bi₂Te₃ and calcium cobaltite directly from the starting powder. The technique offers exceptionally high deposition rates while avoiding high-temperature processes during film formation. Using PAD, dense Bi₂Te₃ films with controlled composition (undoped, n-type, and p-type) can be fabricated ranging from conventional μm-thick coatings to bulk-like PAD samples with thicknesses in the mm-range. This technology enables the production of thick-film and bulk thermocouples in a single manufacturing process, which allows for a high flexibility in film thickness. The focus of this work is on the systematic investigation of the morphological, structural, and thermoelectric properties of both μm-thick and bulk-like Bi₂Te₃ films processed by PAD. The influence of the PAD-induced microstructure is studied, as well as the effect of post deposition annealing, which is characteristic for PAD-processed materials. This annealing step is typically used to reduce microstrain in the PAD-films and to improve carrier transport properties while maintaining the dense film morphology and the microstructure. The thermoelectric performance is characterized as a function of temperature over the relevant operating range. Seebeck coefficient, electrical conductivity, thermal conductivity, and Hall measurements are used to determine the charge carrier concentration and mobility of charge carriers, with a particular emphasis on anisotropic transport properties. Structure-property relationships are investigated by comparing μm-thick and bulk PAD Bi₂Te₃ samples before and after thermal annealing and in dependence on temperature. This provides insights into the potential of PAD as a versatile fabrication process for thermoelectric materials across different thickness scales.