Synergistic Texturing and Bi/Sb-Te Antisite Doping Secure High Thermoelectric Performance in Bi0.5Sb1.5Te3-Based Thin Films

Bi2Te3-based thin films are attracting increasing attention due to their considerable wearability and flexibility feature. However, the relatively low performance compared to their bulk counterparts limits their development and wider application. In this work, synergistic texturing and Bi/Sb-Te antisite doping are used to achieve a high room-temperature ZT of ≈1.5 in p-type Bi0.5Sb1.5Te3 thin films by a magnetron sputtering method. Structural characterization confirms that carefully tuning the deposition temperature can strengthen the texture of as-prepared polycrystalline Bi0.5Sb1.5Te3 thin films, leading to significantly enhanced carrier mobility and electrical conductivity. Simultaneously, rational engineering of the deposition temperature can induce antisite doping between Bi/Sb and Te, which can reduce the carrier concentration and make it closer to the optimized level. In turn, a high power factor of 45.3 µW cm−1 K−2 and a maximized ZT of ≈1.5 at room temperature are obtained. This high power factor and ZT are highly competitive to other state-of-the-art p-type thin-film-based thermoelectric materials, showing great potentials for practical applications.