Photonic-band structures in macroporous silicon

Macroporous Si was prepared by electrochemical etching at a linearly varyin g applied voltage. A relationship between the process parameters (illuminat ion intensity, current density, and applied voltage) was derived in a diffu sion-drift model. The experimental dependences of the ratio of the photohol e concentration to the current density on the distance between the illumina ted surface and pore bottom were shown to agree with the diffusion-drift mo del for nonequilibrium-hole transport provided that the anode thickness exc eeds the diffusion length of holes and the pore radius is comparatively lar ge. The photonic band gap of the two-dimensional macroporous Si structure w as calculated by the plane-wave method. The transmittance of macroporous Si was measured. The effect of surface recombination on the lifetime of noneq uilibrium charge carriers was assessed.