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Silicon coupled with plasmon nanocavities generates bright visible hot luminescence


To address the limitations in device speed and performance in silicon-based electronics, there have been extensive studies on silicon optoelectronics with a view to achieving ultrafast optical data processing1,2,3. The biggest challenge has been to develop an efficient silicon-based light source, because the indirect bandgap of silicon gives rise to extremely low emission efficiencies. Although light emission in quantum-confined silicon at sub-10 nm length scales has been demonstrated4,5,6,7, there are difficulties in integrating quantum structures with conventional electronics8,9. It is desirable to develop new concepts to obtain emission from silicon at length scales compatible with current electronic devices (20–100 nm), which therefore do not utilize quantum-confinement effects. Here, we demonstrate an entirely new method to achieve bright visible light emission in ‘bulk-sized’ silicon coupled with plasmon nanocavities at room temperature, from non-thermalized carrier recombination. The highly enhanced emission (internal quantum efficiency of >1%) in plasmonic silicon, together with its size compatibility with current silicon electronics, provides new avenues for developing monolithically integrated light sources on conventional microchips.

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Figure 1: Hot luminescence from silicon coupled to a plasmon nanocavity.
Figure 2: Resonantly enhanced hot luminescence in plasmonic silicon.
Figure 3: Polarization-selective spectra for resonant and non-resonant plasmonic silicon devices.


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This work was supported by the US Army Research Office (grant nos W911NF-09-1-0477 and W911NF-11-1-0024) and the National Institutes of Health through the NIH Director's New Innovator Award Program (1-DP2-7251-01). C.O.A. is supported by the US Department of Defense, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship. The authors thank A. Boukai (Michigan) and J. Spanier (Drexel) for providing vapour-liquid-solid (VLS)-grown silicon nanowire substrates.

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C-H.C. and R.A. developed the concept and design of the devices. C-H.C. fabricated the devices and performed optical measurements. C.O.A. performed the numerical simulations, fabricated devices and performed optical measurements at 532 nm excitation. J.P. fabricated and carried out the emission experiments on bowtie structures. C-H.C., C.O.A. and R.A. analysed the results and wrote the manuscript.

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Correspondence to Ritesh Agarwal.

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The authors declare no competing financial interests.

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Cho, CH., Aspetti, C., Park, J. et al. Silicon coupled with plasmon nanocavities generates bright visible hot luminescence. Nature Photon 7, 285–289 (2013).

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