Investigation Of 1-D Porous Silicon Dioxide Photonic Crystal For Mid-infrared Application

The thermal isolation structure of substrate and infrared radiation was the major problems that limit the resolution of non-cooling infrared pyroelectric thin film IR detector. In this thesis, a possible solution was investigated to construct porous Si-based 1D multilayer structure by electrochemical etching method. The rapid thermal oxidation (RTO) was applied to make the high porosity layer fully oxidized while the low porosity layer partially oxidized, hence the alternating periodical multilayer construct a PBG structure. This structure can be used as the substrate for non-cooling infrared pyroelectric thin film IR detector. We also investigated the effect of different oxidation condition on optical properties of porous silicon dioxide. Then we testify the possibility of widening band-gap by various methods.Since the porous silicon dioxide itself owns the property of thermal isolation, it can not only block the radiation for mid-IR but also can isolate the heat.In the first chapter, the basic knowledge of photonic crystal, especially one dimensional (1D) photonic crystal was introduced.In chapter 2, the oxidation behavior of porous silicon was investigated in order to find the best oxidation condition.In chapter 3, the focus was paid on designing 1D photonic crystal using Transfer Matrix Method (TMM) and some effects were discussed on central wavelength, e.g. period, ratio of refractive index, etc. Then the simulation results were given.In chapter 4, some validation techniques were given to test the photonic crystal structure, e.g. gravimetric analysis, Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman scatter spectra.In chapter 5, we groped the possibility of 1D photonic crystal working on far-IR using the similar technique. Results showed these need to be improved.The end of the thesis came to a conclusion of whole work and a expectation of 1D porous SiO₂ photonic crystal, also an outlook was given.