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.