P-type macroporous silicon for two-dimensional photonic crystals

Macroporous silicon with two-dimensional periodicity has been produced by electrochemical etching, using a p-type doped silicon substrate. The structure shows photonic energy gaps in the infrared region, as demonstrated by variable angle reflectance measurements. The agreement between measurement and band calculations confirms the high quality of the samples. The use of an optimized electrolyte allows the fabrication of very high quality samples, with high aspect ratio and low roughness both at the surface and on the pore walls. The best results are obtained with aprotic and protophilic solvents. (C) 2002 American Institute of Physics.