Quantum Effects in the Thermoelectric Power Factor of Low-Dimensional Semiconductors

TLDR

We investigate how confinement length L and thermal de Broglie wavelength Λ interplay to optimize the thermoelectric power factor of semiconducting materials. An analytical one‑band model for nondegenerate semiconductors is used to derive a formula describing quantum effects on the power factor of low‑dimensional semiconductors. The power factor is higher in one‑ and two‑dimensional semiconductors when L < Λ, whereas bulk materials outperform lower‑dimensional ones when L > Λ.

Abstract

We theoretically investigate the interplay between the confinement length L and the thermal de Broglie wavelength Λ to optimize the thermoelectric power factor of semiconducting materials. An analytical formula for the power factor is derived based on the one-band model assuming nondegenerate semiconductors to describe quantum effects on the power factor of the low-dimensional semiconductors. The power factor is enhanced for one- and two-dimensional semiconductors when L is smaller than Λ of the semiconductors. In this case, the low-dimensional semiconductors having L smaller than their Λ will give a better thermoelectric performance compared to their bulk counterpart. On the other hand, when L is larger than Λ, bulk semiconductors may give a higher power factor compared to the lower dimensional ones.