Abstract

ielectric Mie resonators have attracted a great deal of attention over the past few years thanks to their remarkable capabilities in manipulating light propagation at the nanoscale1,2,3. However, the practical implementation of technological products is still elusive. Important limits are the absence of a high-performing material and a fabrication method that can be easily integrated into modern micro-electronic devices at affordable costs. Here, we provide theoretical and experimental evidence of solid state dewetting of ultra-thin silicon and silicon-germanium films on insulators as an alternative fabrication method and semiconductor material for dielectric Mie resonator applications4-7. These dielectric resonant particles can be obtained over very large surfaces4 on arbitrary silica substrates5. Remarkably, this self-assembly process is independent on the sample size. Furthermore, the Si(Ge) islands can be precisely organised in uniform arrays and complex oligomers arrangements6 featuring low size dispersion. Their composition profile can be controlled a posteriori via a Ge condensation process to form core-shell Si/SiGe islands7,8 and their diffusion spectrum can be electrically tuned by changing the refractive index of the environment. As an example, we demonstrate SiGe- based Mie resonator arrays functioning as colour pass-band filters across the full visible spectral range9. The filters function both in transmission and diffusion and are fabricated using a methodology compatible with C- MOS technology. We note that the use of SiGe-based alloys in novel electronic devices, such as FET and C- MOS transistors, is nowadays extremely important. Because of this, opening the field of dielectric MRs to SiGe-based semiconductor alloys is an important step forward towards the integration of photonics with electronic devices.