High-Throughput Measurement of the Seebeck Coefficient and the Electrical Conductivity of Lithographically Patterned Polycrystalline PbTe Nanowires

A high-throughput method for measuring the Seebeck coefficient, S. and the electrical conductivity, sigma of lithographically patterned nanowire arrays is described. Our method involves in the microfabrication of two heaters and two Ag/Ni thermocouples, literally on top of an array of polycrystalline PbTe nanowires synthesized on a Si3N4 wafer using the lithographically patterned nanowire electrodeposition (LPNE) method. This strategy eliminates the transfer and manipulation of nanowires as a prerequisite for carrying out measurements on these wires of thermoelectric metrics. With these devices, we have measured the influence of the thermal annealing temperature on the thermoelectric properties of nine arrays of 60 nm x200 nm x 200 mu m PbTe nanowires and we find that at an optimum annealing temperature of 453 K, the S at 300 K is increased from -41 mu V/K for unannealed wires to -479 mu V/K 80% larger in magnitude than the S(-260 mu V/K) of bulk PbTe.