Bottom-up Silicon Nanowire Arrays for Thermoelectric Harvesting

Ordered dense arrays of p-type Si nanowires produced with a VLS method have been surveyed as anew active material to produceall-Si thermoelectric energy harvesters. The thermoelectric properties of themeta-material consisting of bundles of thousands of 10 μm long Si nanowires (with a mean diameter of 100 nm)were measured making use of an integrated self-test element(heater/thermometer) that allowsanaccurate control of the temperature gradient in thesilicon micromachined structure used to assemble the thermocouples. The measuredSeebeck coefficient S and thermal conductivity ktogether with the resistivity reported in literature for similar boron doped Si nanowires suggest a ZT figure of merit at ambient temperature between 0.30 and 0.93, showing that proposed nanowire arrays can be a promising candidate for enhancing Si thermoelectric properties.