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 15 nm and 6 nm for microdisks with a diameter of 8.8 mu m and 23.7 mu m, respectively. The advantages of such size-controlled Si-NCs/SiO2 embedded in microdisk arrays for Si-based photonic application will be discussed.