Exceptional Thermoelectric Power Factors in Hyperdoped, Fully Dehydrogenated Nanocrystalline Silicon Thin Films

TL;DR

This study demonstrates that removing hydrogen from boron-hyperdoped nanocrystalline silicon thin films significantly enhances their thermoelectric power factor, making them competitive with traditional thermoelectric materials for low-temperature applications.

Contribution

It reveals that dehydrogenation in hyperdoped nanocrystalline silicon greatly improves its thermoelectric power factor, a novel approach not extensively explored before.

Findings

Power factor increased up to 33 mW K$^{-2}$m$^{-1}$ at 300 K.

Dehydrogenation enhances thermoelectric performance of nanocrystalline silicon.

Nanocrystalline Si becomes a cost-effective alternative to Bi$_2$Te$_3$.

Abstract

Single-crystalline silicon is well known to be a poor thermoelectric material due to its high thermal conductivity. Most excellent research has focused on ways to decrease its thermal conductivity while retaining acceptably large power factors (PFs). Less effort has been spent to enhance the PF in poly and nanocrystalline silicon, instead. Here we show that in boron-hyperdoped nanocrystalline thin films PF may be increased up to 33 mW K$^{-2}$m$^{-1}$ at 300 K when hydrogen embedded in the film during deposition is removed. The result makes nanocrystalline Si a realistic competitor of Bi$_2$Te$_3$ for low-temperature heat harvesting, also due to its greater geo-availability and lower cost.