Investigation Of One Dimensional Photonic Crystal Based On Porous Silicon

Photonic crystal, which consists of alternating layers of different refractive index, is well known as a brand new material of great optical function. It has considerable novel characters named photonic band gap(PBG), which means the light can't transmit the photonic crystal when light's frequency in the PBG. Porous silicon is an interesting optical material. Large refractive index variation with porosity, together with relatively simple fabrication techniques and low manufacturing costs, make porous silicon a very promising candidate for photonic applications. The porosity of the porous silicon is a linear function of the current density for a specific HF concentration. A periodic alternating current between two different current densities is an easy way to form multilayer porous silicon structures, results in the formation of typical 1-D photonic crystals.In this paper, the fabrication of one dimensional photonic crystal made from porous silicon was explored. The paper dicucuss the influence of the technical conditions on fabrication of the 1-D photonic crystal and optimize the optical constant of the 1-D photonic crystal from simulation.Chapter I introduced the basic conceptions of the photnic crystal briefly. And then the development status of photnic crystal and the problem photonic crystal faced have been introduced. The aim of this paper has been disscussed.In chapter II, we introduced the basic theories and fabrication of the 1-D porous silicon photonic crystal. The paper dicucuss the influence of current density , HF concentration, the type of substrate, room temperature and oxidation time on the 1-D photonic crystals.The design of the 1-D porous silicon photonic crystal is studied in Chapter III. By optimizing optical parameters, we simulated their reflectivity spectra by means of the transfer-matrix method (TMM). Then we analyse the influence of the period , the ratio of refractive index , the wavelength of midgap to the reflectivity spectra.The band gap of structure with the different defect has also been discussed by the TMM.Chapter IV introduced the testing result of the 1-D porous silicon photonic crystal.In our work, anodization of p-type silicon was carried out and one dimensional photonic crystal based porous silicon has been materialized. This porous silicon 1-D photonic crystal demonstrates a photonic band gap (PBG) as wide as more than 250 run, while its midgap wavelength is about 1600nm. Then we have fabricated the defect of 2λ in aforementioned structure successful.