Silicon quantum dot optical properties and synthesis: Implications for photovoltaic devices

We study key optical properties for designing an absorber layer with silicon quantum dots (Si-QDs), including the absorptivity of the material, whether the character of the bandgap is direct or indirect, and the relation between absorption and photoluminescence. We report necessary synthesis conditions in order to control size, size distribution, and crystallinity of Si-QDs. This is important for applications of Si-QDs in photovoltaics, where they excite interest due to their size-tunable bandgap, potentially cheap fabrication, and possible enhancement of solar energy conversion efficiency through mechanisms such as multiple exciton generation.