Photonic-Band Structures in Macroporous Silicon

Macroporous Si was prepared by electrochemical etching at a linearly varying applied voltage. A relationship between the process parameters (illumination intensity, current density, and applied voltage) was derived in a diffusion–drift model. The experimental dependences of the ratio of the photohole concentration to the current density on the distance between the illuminated surface and pore bottom were shown to agree with the diffusion–drift model for nonequilibrium-hole transport provided that the anode thickness exceeds the diffusion length of holes and the pore radius is comparatively large. The photonic band gap of the two-dimensional macroporous Si structure was calculated by the plane-wave method. The transmittance of macroporous Si was measured. The effect of surface recombination on the lifetime of nonequilibrium charge carriers was assessed.