Optical spectra of two-dimensional photonic crystal bars based on macroporous Si

Abstract

Two-dimensional (2D) photonic crystal (PC) bars with 6 and 21 periods were fabricated by simultaneous photoelectrochemical etching of macropores and trenches in a pre-patterned silicon wafer. The structures had square lattice of cylindrical pores and were terminated by nonmodulated silicon pre-layers. The infrared reflection spectra of the PC bars have been simulated using scattering matrix method. In order to take into account the roughness of pore inner surface an additional silicon layer around the pores was introduced with a fitted complex refractive index. A comparison between the simulated refection spectra and those obtained experimentally demonstrates a satisfactory agreement in the region of secondary photonic band gaps.