Recent advances in silicon-based nanostructures for thermoelectric applications

In this work, implementations of silicon-based thermoelectric nanomaterials are reviewed. Approaches ranging from nanostructured bulk-i.e., macroscopic materials presenting nanoscale features-to more complex low-dimensional materials are covered. These implementations take advantage of different phonon scattering mechanisms and eventual modifications of the electronic band-structure for the enhancement of the thermoelectric figure of merit. This work is focused on the recent advances in silicon and silicon-based thermoelectric nanomaterials of the last decade-at both the theoretical and experimental level-with the spotlight on the most recent works. Different nanostructures and their fabrication methods are detailed, while the thermoelectric performances and the feasibility of their integration into functional micro-harvester generators are compared and discussed. This Research Update first covers the advances in nanostructured bulk, such as nanometric-sized polycrystals or defect-induced materials. Subsequently, it reviews low-dimensional materials, namely, thin films and nanowires. Later, other complex structures based on nanoporosity, superlattices, or core-shell schemes are detailed. Finally, it is devoted to present examples of the successful implementation of nanostructured silicon into functional thermoelectric devices.