Ultrathin MEMS thermoelectric generator with Bi₂Te₃/(Pt, Au) multilayers and Sb₂Te₃ legs

Multilayer structure is one of the research focuses of thermoelectric (TE) material in recent years. In this work, n-type 800 nm Bi₂Te₃/(Pt, Au) multilayers are designed with p-type Sb₂Te₃ legs to fabricate ultrathin microelectromechanical systems (MEMS) TE devices. The power factor of the annealed Bi₂Te₃/Pt multilayer reaches 46.5 μW cm^-1 K^-2 at 303 K, which corresponds to more than a 350% enhancement when compared to pristine Bi₂Te₃. The annealed Bi₂Te₃/Au multilayers have a lower power factor than pristine Bi₂Te₃. The power of the device with Sb₂Te₃ and Bi₂Te₃/Pt multilayers measures 20.9 nW at 463 K and the calculated maximum output power reaches 10.5 nW, which is 39.5% higher than the device based on Sb₂Te₃ and Bi₂Te₃, and 96.7% higher than the Sb₂Te₃ and Bi₂Te₃/Au multilayers one. This work can provide an opportunity to improve TE properties by using multilayer structures and novel ultrathin MEMS TE devices in a wide variety of applications.