The fabrication of nanoscale Bi2Te3/Sb2Te3 multilayer thin film -based thermoelectric power chips

In this paper, we report our method of fabricating nanoscale multilayered Bi2Te3/Sb2Te3 thin film-based integrated thermoelectric devices, and detail the voltage and power produced by the device. The multilayered Bi2Te3/Sb2Te3 thin film was grown via e-beam evaporation; it had 20 alternating Bi2Te3- and Sb2Te3-layers, each layer being 1.5 nm thick. We characterized the film using high-resolution transmission electron microscopy (HRTEM), revealing its excellent cross-sectional structure without any obvious interface defects. The Bi2Te3/Sb2Te3 multilayer films were investigated by synchrotron X-ray scattering. An integrated device including 128 x 256 thermoelectric elements was fabricated from the multilayered film. An open-circuit voltage of 51 mV and a maximum power of 21 nW were produced from this 30 nm-thick Bi2Te3/Sb2Te3 multilayer TE device, and a temperature gradient of about 0.5 K/mu m was established across the multilayered film. We found that the nanoscale multilayer structure significantly affects the voltage and power produced. The fabrication of the integrated thermoelectric devices is compatible to that of generating standard integrated circuits (ICs), and is scalable for producing higher voltage and power, or achieving solid-state cooling for on-chip applications.