Performance improvement of a thin film thermoelectric generator via optimisation of the deposition parameters

Abstract

Thin film thermoelectric generators (TEGs) offer a compact and scalable solution for harvesting waste heat in microelectronic and flexible systems. However, their performance is highly influenced by material properties, fabrication parameters, and device geometry. This work presents a systematic optimization of Bi₂Te₃ and Sb₂Te₃ thin films for a high-performance TEG. The thin films were deposited via radio frequency (RF) magnetron sputtering under varying power conditions and characterized using XRD, FESEM, EDX, Hall measurements, and Seebeck coefficient analysis. The optimal sputtering powers were identified as 75 W for Bi₂Te₃ and 30 W for Sb₂Te₃, yielding high crystallinity and balanced electrical conductivity with favourable Seebeck values. A thin film TEG consisting of six n-type/p-type leg pairs was fabricated using these conditions and subjected to post-deposition annealing to improve performance. The TEG annealed at 200 °C demonstrated a peak power output of 0.84 μW at ∼120 °C ΔT, indicating enhanced crystallinity and reduced internal resistance. Dimensional optimization further revealed that wider and shorter TE legs significantly improve the output by minimizing internal resistance. The results highlight the importance of integrating material, process, and device-level optimization for the development of efficient and scalable thin film thermoelectric systems.