Strategies for thermoelectric power factor: from tin-based materials to device applications
摘要
This study explores the thermoelectric properties of AlSnTe thin films, focusing on how post-annealing treatment influences the thermoelectric power factor. Scanning electron microscopy (SEM) analysis shows that the as-deposited films have a smooth surface with large grains, reaching approximately 1.84 μm in size. Post-annealing for 1 to 3 h induces structural changes, with the most prominent transformation observed after 3 h, where larger grains fragment into smaller, metallic-like grains. Electrical measurements reveal an increase in conductivity from 360.87 S/cm (as-deposited) to 432.94 S/cm after 3 h of annealing, attributed to improved grain connectivity and reduced scattering effects. Simultaneously, charge carrier concentration decreases from 3.6 × 1019 cm−3 to 2.6 × 1019 cm−3, likely due to the vitalization of Te atoms from the surface and formation of conductive secondary phases. However, charge carrier mobility increases from 66.32 cm²V⁻¹s⁻¹ to 108.04 cm²V⁻¹s⁻¹, primarily due to formation of larger, more ordered grains, which reduces grain boundary scattering. The Seebeck coefficient exhibits p-type behavior, increasing from 128.4 µV/K to 169.6 µV/K as temperature rises from 300 K to 450 K. The highest power factor of 10.57 µWcm⁻¹K⁻² is observed in the sample annealed for three hour at 450 K, demonstrating an optimal balance between the Seebeck coefficient and electrical conductivity. These results highlight the impact of post-annealing on enhancing thermoelectric performance, making AlSnTe a promising candidate for energy conversion applications.