Visible range whispering-gallery mode in microdisk array based on size-controlled Si nanocrystals

Microdisks based on in-plane embedded size-controlled Si $nanocrystal∕SiO2$ superlattices (⁠$Si-NCs∕SiO2$ SLs) were mass-fabricated arranged in well-ordered arrays. The microdisks were fabricated with size irregularity of below 0.2% over large-scale areas. Overlapping whispering-gallery modes (WGM) of the visible nanocrystalline-silicon luminescence were observed. A comparison between analytical calculation and experimental results is reported. We found that only one axial and one radial WGM exist due to their thin disk thickness and birefringence characteristic of $Si-NCs∕SiO2$ SLs, and that the mode spacing is $15nm$ and $6nm$ for microdisks with a diameter of $8.8μm$ and $23.7μm$⁠, respectively. The advantages of such size-controlled $Si-NCs∕SiO2$ embedded in microdisk arrays for Si-based photonic application will be discussed.