EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Silicon's physical properties, easy manufacturing, and cheapness promoted its industrial employment as a leading material for different applications. Si indirect bandgap is a great limit for photonics. The scientific community has devoted efforts to realizing a new class of efficient light emitters based on Si platforms. By a low-cost and industrially compatible method, we realized an ultrathin and dense vertical array of Si nanowires (NW) that efficiently emit light in the visible at RT due to quantum confinement. Fractal arrays of Si NWs exhibiting a strong light trapping from visible to near-IR were synthesized without any lithography or mask. We engineered the realization of multi-wavelength light sources operating at RT by decorating fractal Si NW with Er-doped yttrium oxide deposited by sputtering in oblique angle deposition configuration, placing the substrate at different angles with respect to the normal direction to the target. Er in yttrium oxide is characterized by intense IR emission strategic for telecom applications. The structural properties and fractal parameters were characterized as a function of deposition settings and correlated to the optical properties. By using different excitation wavelengths, we demonstrate the Er emission is enhanced by the scattering effect driven from the NW's fractal morphology. This material opens new perspectives for the Si platforms as an active medium in light sources for Si photonics and telecommunication applications.