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Miniaturized silicon-based nanostructures are highly desirable for on-chip communication and sensing due to their precise fabrication methods. However, silicon’s low photoluminescence quantum yield limits its use in light-emitting devices. Here, we propose a way to increase the broadband photoluminescence quantum yield of a silicon-based emitter by using plasmonic cavity modes in a metasurface. The cavity resonances’ spectral positions are optimized for efficient multiphoton absorption in the near-infrared and broadband photoluminescence enhancement in the visible range. The experimental characterization of nanocavity modes under different excitation conditions reveals a strong correlation between numerically estimated Purcell factor (Fp(total)∼103) and spectrally resolved photoluminescence lifetime measurements. The results demonstrate that plasmonic cavity modes boost silicon’s quantum efficiency to 0.35% using multiphoton excitation within a record-low silicon volume (∼105 nm3). Our research enables precise tuning of plasmonic cavity resonances, facilitating the control of indirect bandgap semiconductor emission for nanoscale silicon-based light sources and sensors.
Larin et al. (Thu,) studied this question.