Fabrication of three dimensional porous silicon distributed Bragg reflectors

Three-dimensional distributed Bragg reflectors, which reflect all incident wavelengths, have been fabricated with micrometer dimensions in porous silicon, resulting in white reflective surfaces when viewed over a wide angular range. Large area arrays of several mm(2) containing many individual micrometer-size pixellated reflectors that can be tuned to reflect a narrow or wide range of wavelengths are designed to appear either as constant or changing reflective images to the naked eye. This work opens avenues in controlling the reflection of light in all directions for applications in wide-angle displays, broadband reflective surfaces for resonant white light emission from semiconductor nanocrystals, and three-dimensional microcavities.