Ge islands and photonic crystals for Si-based photonics

We report on the integration of Ge/Si self-assembled islands into two-dimensional photonic crystals for silicon-based photonics. The photonic crystals are processed by e-beam lithography on silicon-on-insulator substrates. The room temperature photoluminescence of the Ge islands is used to probe the photonic structures, especially those with defect-microcavities intentionally processed in the photonic crystals. We show that for H2 microcavities, the modes preferentially coupled out of the crystal plane are non-degenerate. We also show that the evolution of the microcavity photoluminescence with pump power depends on the air filling factor of the photonic crystals. A superlinear dependence is obtained for a large hole radius to period ratio.