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A. Structure Design Control of dimensions (a, d, and h) to (i) Concentrate pump energy inside active region for enhancement of Purcell spontaneous emission rate. (ii) Improve light extraction based on coherent scattering in periodic array. B. Structure Fabrication - The Si-based materials are patterned with hexagonal-lattice air-hole photonic crystals (PhCs)


1 September 2008

Efficient silicon-based light source could enable full monolithically integrated photonic circuits leveraging on Si-CMOS technology. However, the brightness of light emission from silicon-based materials would be insufficient due to the low radiation in the indirect-gap system. As an alternative approach, IME researchers designed and fabricated triangular-lattice air-hole photonic crystal patterns in the silicon rich oxide/SiO2 multilayer stacks to improve the light extraction by providing a convenient way of redistribution the light energy in desired form and orientation. As a result, the intensity and profile of spontaneous emission were efficiently modulated by controlling the optical modes via varying the structural dimensions of photonic crystals. With lattice constant/radius of 700 nm / 280 nm, the room-temperature photoluminescence intensity was enhanced up to ~9 times in the vertical direction. The mechanisms therein could be theoretically analyzed based on coherent scattering and quantum electrodynamics' effects, well consistent with the experiment observation.

The paper, "Strong vertical light output from thin silicon rich oxide/SiO2 multilayers via in-plane modulation of photonic crystal patterns" was featured on the in Applied Physics Letters, Vol. 93, Issue 9, 091901 (2008).