Fabrication of Bi₂Te₃ and Sb₂Te₃ Thermoelectric Thin Films using Radio Frequency Magnetron Sputtering Technique

Through various studies on thermoelectric (TE) materials, thin film configuration gives superior advantages over conventional bulk TEs, including adaptability to curved and flexible substrates. Several different thin film deposition methods have been explored, yet magnetron sputtering is still favorable due to its high deposition efficiency and scalability. Therefore, this study aims to fabricate a bismuth telluride (Bi₂Te₃) and antimony telluride (Sb₂Te₃) thin film via the radio frequency (RF) magnetron sputtering method. The thin films were deposited on soda lime glass substrates at ambient temperature. The substrates were first washed using water and soap, ultrasonically cleaned with methanol, acetone, ethanol, and deionized water for 10 min, dried with nitrogen gas and hot plate, and finally treated under UV ozone for 10 min to remove residues before the coating process. A sputter target of Bi₂Te₃ and Sb₂Te₃ with Argon gas was used, and pre-sputtering was done to clean the target's surface. Then, a few clean substrates were loaded into the sputtering chamber, and the chamber was vacuumed until the pressure reached 2 x 10^-5 Torr. The thin films were deposited for 60 min with Argon flow of 4 sccm and RF power at 75 W and 30 W for Bi₂Te₃ and Sb₂Te₃, respectively. This method resulted in highly uniform n-type Bi₂Te₃ and p-type Sb₂Te₃ thin films.