Thermoelectric properties of Pb-doped bismuth telluride thin films deposited by magnetron sputtering

• Nanocrystalline n-type Bi2Te3 films are deposited by magnetron sputtering.
• Pb doping increases the Seebeck coefficient of Bi2Te3 thin films.
• Pb doping reduces the carrier thermal conductivity of Bi2Te3 thin films.
• Optimal Pb doping enhances the power factor of Bi2Te3 thin films.

Nanocrystalline n-type bismuth telluride (Bi2Te3) thin films doped with lead (Pb) were deposited by radiofrequency magnetron sputtering. The effects of Pb doping on the carrier concentration and the thermoelectric properties of the Bi2Te3 thin film were investigated. Optimization of the carrier concentration significantly increased the Seebeck coefficient of the Bi2Te3 film and reduced the carrier thermal conductivity. These phenomena contributed to the enhancement of the thermoelectric properties of the Bi2Te3 film. Power factors of 2.50 and 2.15 mW K−2 m−1 were achieved at 473 K for the as-deposited and annealed Bi2Te3 films with Pb doping concentration of 0.38 at.%, respectively. The experimental data demonstrate that Pb doping can effectively control the carrier concentration of the n-type Bi2Te3 film. The Pb-doped Bi2Te3 film is a promising material for thermoelectric microdevices.