Thermoelectric figure of merit calculations for semiconducting nanowires

A model for the thermoelectric properties of nanowires was used to demonstrate the contrasting influences of quantization and degeneracy on the thermoelectric power factor. The prevailing notion that quantum confinement benefits the thermoelectric power factor is supported by the model when a single-subband dominates transport. When transport involves multiple subbands, the thermoelectric power factor in fact decreases (to ∼62% of the bulk value) as the wire radius is initially reduced. This work correctly models the power factor for wire sizes ranging from the nanoscale to bulk and settles the discrepancies between theoretical and measured thermoelectric power factors in nanowires and other nanoscale systems.