Multi-layered-stack thermoelectric generators using p-type Sb2Te3 and n-type Bi2Te3 thin films by radio-frequency magnetron sputtering

Abstract To provide power to electronic sensors operating at low power, we prepared multi-layered-stack thermoelectric generators using radio-frequency (RF) magnetron sputtering. Prior to the preparation of thermoelectric generators, Sb 2 Te 3 and Bi 2 Te 3 thin films were deposited on glass substrates followed by carrying out thermal annealing at temperatures ranging from 200 to 400 °C in order to investigate and improve their thermoelectric properties. Both the films exhibited the maximum power factor values measured at room temperature, namely, 12.7 μW/(cm·K 2 ) for Sb 2 Te 3 and 10.2 μW/(cm·K 2 ) for Bi 2 Te 3 , at an annealing temperature of 300 °C. Therefore, the films annealed at 300 °C are suitable for fabricating multi-layered-stack thermoelectric generators. To prepare thermoelectric generators, Sb 2 Te 3 and Bi 2 Te 3 thin films were deposited on the top and bottom sides of 0.3 mm-thick glass substrates, respectively. Eleven sample pieces were connected in series by spraying silver paste to obtain the multi-layered-stack thermoelectric generators. Generators with dimensions of 20 × 30 mm 2 and a thickness of 7 mm were fabricated. The thermoelectric generators exhibited an open circuit voltage of 32 mV and maximum output power of 0.15 μW at a temperature difference (on both ends) of 28 K.