Selectively enhanced emission and suppression in Si0.5Ge0.5/Si multiple quantum wells by photonic crystals.

Selective enhancement and suppression of the photoluminescence arising from Si_0.5Ge_0.5/Si multiple quantum wells by photonic crystals (PCs) have been demonstrated. The formation of the stop band in PCs is designed to be a filter as well as a reflector. It is found that the self-assembled PCs are able to selectively enhance the luminescence of the type-II transitions at the interface between Si and Si_0.5Ge_0.5/Si layers and suppress the emission from Si. Our working principle shown here can be extended to many other material systems and should be very useful for creating high power solid-state emitters. [ABSTRACT FROM AUTHOR]