Abstract

Photonic band gap materials, or simply called photonic crystals, had recently attracted many attentions for their potential of controlling light wave in a way similarly to semiconductors controlling particle waves of carriers.¹ With intentionally designed defects, light cavities, waveguides, reflectors, filters, and other functional components can be integrated in the same photonic crystals. Thus they will form photonic circuitry, performing functions similar to the roles played by electronic circuitry. To have the full functions, light sources are also important. On the other hand, the mature fabrication technology using Si could possibly help the spread of photonic circuitry based on Si. However, light generation from Si is hindered by the indirect- bandgap nature. Here we report the possibility of breaking the indirect-bandgap limitation to efficiently generate light from Si. We theoretically and experimentally discovered that carrier localization could enhance radiative recombination corresponding to bandgap energy of Si for orders of magnitudes. Nearly lasing actions corresponding to Si bandgap energy were even observed with the enhanced radiative recombination.

© 2002 Optical Society of America