Influence of Annealing Atmospheres on the Structural and Thermoelectric Characteristics of Sb2Te3 Thin Film

Antimony telluride (Sb₂Te₃) thin films were deposited on 1-μm SiO₂ / Si-wafer substrates to a thickness of approximately 250 nm by using pulse-dc magnetron sputtering method, and their thermoelectric (TE) properties were evaluated. This study examined the impact of post-annealing at 250°C under vacuum, argon (Ar), and nitrogen (N₂) atmospheres on the thermoelectric (TE) properties. The surface morphology, crystalline structure, and atomic composition were analyzed for both as-deposited and post-annealed thin films using field emission scanning electron microscopy (FE-SEM), grazing incidence X-ray diffraction (GI-XRD) and energy dispersive X-ray spectroscopy (EDS), respectively. The results revealed that post-annealing significantly influenced the thin film structure, enhancing the Sb₂Te₃ crystal orientations, particularly the (015) and (101̅0) peaks. Additionally, Hall effect measurement performed after post-annealing confirmed the electrical properties of all samples, providing further understanding of their electrical properties. For the thermoelectric (TE) properties, low temperature Seebeck coefficient analysis confirmed the p-type character of Sb₂Te₃. The argon post-annealed sample exhibited the highest Seebeck coeefficient of 1.0 x 10^-4 V/K, corresponding to a maximum power factor (PF) of 4.40 x 10^-4   W/m K^-2. The results clearly show that post-annealing temperature directly affected both the electrical and thermoelectric characteristics.