Reduced Thermal Conductivity in Silicon Thin-Films via Vacancies

Abstract

An experimental method is defined that reduces the thermal conductivity in Si films by ~90 % compared to control samples, while keeping the thermoelectric power factor almost unchanged. This is done by creating vacancy-rich films via high-energy self-implantation of Si, followed by rapid-thermal annealing. TCAD simulations suggest that this approach is scalable for application in thin-film thermoelectric generators, as an alternative to more expensive and less Earth-abundant materials such as bismuth telluride. This approach to Si thermoelectrics could be straight-forward for scale-up to thin-film device dimensions, something that is a major challenge for other methods used for Si thermal conductivity reduction.