Performance demonstration of cavity-free planar multi-stage bileg and unileg silicon-nanowire thermoelectric generators

The thermoelectric (TE) generator is expected to play an important role in the operation of tiny-watt capable wireless power supply devices, by converting waste heat energy into electrical energy. This work demonstrates planar cavity-free multi-stage n-type unileg-and bileg Si-nanowire (Si-NW) TE generators. The result shows that the output power of the multi-stage bileg-TE generator increases linearly with increasing the stage number, whereas the rate of increase of the multi-stage unileg-TE generator power output tends to decrease as the stage number increases. Although the power of the multi-stage bileg-TE generator fabricated in this work was smaller than that of the multi-stage unileg-TE generator, due to the large internal resistance of p-type elements, the improved linearity of the bileg-TE generator compared to the unileg-TE generator indicates the potential advantage of the multi-stage bileg-TE generator for large-scale integration.