Growth and transport properties of layered bismuth telluride thin films via radio frequency magnetron sputtering

Bismuth telluride thin films with layered nanostructure have been fabricated by radio frequency (RF) magnetron sputtering. Thin films were deposited at various substrate temperatures and durations with a single Bi₂Te₃ target. The microstructures and chemical compositions of these films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscope (EDS). Electrical transport property and Seebeck coefficient were measured on these thin films. The results show that substrate temperature is a key factor on the microstructure and transport property of bismuth telluride thin films. High temperature is beneficial for the formation of layered nanostructure and the enhancement of power factor. The highest power factor was obtained on the thin film deposited at 400°C. However, Te deficiency was observed in these thin films. Thus thermoelectric property would be further enhanced by optimizing composition of these thin films.