Commensurate germanium light emitters in silicon-on-insulator photonic crystal slabs.

We report on the fabrication and characterization of silicon-on-insulator (SOI) photonic crystal slabs (PCS) with commensurately embedded germanium quantum dot (QD) emitters for near-infrared light emission. Substrate pre-patterning defines preferential nucleation sites for the self-assembly of Ge QDs during epitaxial growth. Aligned two-dimensional photonic crystal slabs are then etched into the SOI layer. QD ordering enhances the photoluminescence output as compared to PCSs with randomly embedded QDs. Rigorously coupled wave analysis shows that coupling of the QD emitters to leaky modes of the PCS can be tuned via their location within the unit cell of the PCS.