Two-and three-dimensional composite photonic crystals of macroporous silicon and lead sulfide semiconductor nanostructures

We describe a new method for direct deposition and growth of nanocyrstalline lead sulfide (PbS) thin films into two-and three-dimensional arrays of macroporous silicon and the formation of composite silicon photonic crystals (PhCs). Infrared transmission measurements exhibit a substantial red-shift of the photonic stop bands from the composite PhCs relative to the PhC substrates. Photoluminescence spectroscopy reveals the effect of slow-light modes on the emission spectra from PbS thin films inside a two-dimensional PhC. Top-view SEM image of a 2D composite photonic crystal with thin layers of PbS nanocrystals covering the pore's walls.