Strong Enhancement of Er 3+ Emission at Room Temperature in Si 3 N 4 Metasurfaces

We report room‐temperature photoluminescence (PL) enhancement at from ion‐implanted Er 3+ ions in Mie‐resonant silicon nitride metasurfaces. Following annealing at , nanocylinders with a radius of exhibit an 18.1‐fold detected PL enhancement relative to a planar film. The measured lifetime decreases from to , corresponding to approximately 9.4‐fold shortening. These observations and electromagnetic simulations are consistent with modified spontaneous‐emission dynamics, although excitation, non‐radiative relaxation, and collection also influence the detected intensity. Annealing increases PL and narrows the radius‐dependent enhancement peak: Gaussian fits give geometric full widths at half maximum of approximately before annealing and after annealing. These widths describe the PL enhancement peak; linking them to the optical resonance requires an independent linewidth measurement. Across implantation energies of , depth and total implanted dose vary together, so the increased PL tracks the larger implanted Er population. This CMOS‐compatible platform combines enhanced telecom‐band Er emission with scalable fabrication and room‐temperature operation, offering potential for compact, integrated light sources.