Simple cubic three-dimensional photonic crystals based on macroporous silicon and anisotropic posttreatment -: art. no. 023524

Three-dimensional structures for photonic crystal applications have been fabricated up to now either by pure bottom-up approaches such as colloidal self-assembly, by pure top-down approaches using very large scale integration technology, or by interference lithography. Here we evaluate a concept enabling large photonic band gaps in simple cubic structures, the manufacturing of which is based on photoelectrochemical etching of strongly modulated macroporous silicon. A subsequent anisotropic etching of the porous structure, which exploits the crystallographic nature of the substrate used, converts the former circular cross section of the pores into a squared one. We theoretically study the dispersion behavior of photonic crystals being fabricated by this developed technique. The band-structure calculations are compiled with respect to the relative pore arrangement and the dielectric volume fraction. We present experimentally realized structures and characterize the photonic crystal optically. The reflectance measurements are in good agreement with corresponding band-structure calculations. Moreover, the introduced process extends the variety of designing and sculpturing three-dimensional microstructures to meet the requirements of a multitude of micro- and nanotechnological applications.