High thermoelectric performance achieved in Bi0.4Sb1.6Te3 films with high (00l) orientation via magnetron sputtering

To obtain p-type Bi-Sb-Te-based thin films with excellent thermoelectric performance, the Bi0.4Sb1.6Te3 target is prepared by combining mechanical alloying with the spark plasma sintering technique. Afterward, Bi0.4Sb1.6Te3 thin films are deposited via magnetron sputtering at variable working pressures. With an increasing working pressure, the frequency of collisions between the argon ions and sputtered atoms gradually increases, the preferred orientation of (00l) increases, and the sputtering rate decreases. The Seebeck coefficient increases from similar to 140 mu V/K to similar to 220 mu V/K as the carrier concentration decreases along with an increasing working pressure. Furthermore, the decrease in carrier concentration and acceleration of carrier mobility also affect the change in electrical conductivity. The maximum power factor of the p-type Bi0.4Sb1.6Te3 thin film deposited at 4.0 Pa and at room temperature exceeds 20.0 mu W/cm K-2 and is higher than that of most p-type Bi-Sb-Te-based films.