Silicon de novo: energy filtering and enhanced thermoelectric performances of nanocrystalline silicon and silicon alloys

Second-phase precipitation in nanocrystalline silicon may lead to improved thermoelectric power factors (up to ≈15 mW K−2 m−1 at room temperature) and high figures of merit. In this review, energy filtering is shown to provide an explanatory framework for these findings, helping predict strategies to further improve nanocrystalline silicon efficiency in thermal harvesters.