Heterogeneous integration of TiO₂ epitaxial growth for one-dimensional photonic crystal:An experimental and theoretical analysis

An experimental realization of a new type of one-dimensional photonic crystal has been proposed, based on the periodic layer-by-layer structure of TiO₂. The multilayer deposition of TiO₂ nanoparticle colloidal suspension forms a periodic arrangement of a one-dimensional photonic crystal. It has been able to control and block well defined unwanted radiation or selective harm UV radiation. The fundamental property of photonic crystals is their Photonic bandgap (PBG), which is to be around "225nm<λ<350 nm", and also exhibit structure colour properties. Periodic multilayer structures of TiO₂ on a glass substrate have been deposited by spin coating technique, at different rpm, which affects the thickness of subsequently deposited layers and effective refractive index. FESEM provides a cross-section image of deposited structure for eight layers and thickness, which is in good agreement of calculated one by a profilometer. The X-ray diffraction pattern shows the growth of the epitaxial surface as well as the generation of phase junctions (i.e., the formation of anatase, rutile, and brookite phases of TiO₂). Due to these formations, the proposed structure in this study has less number of the defects, and so, there is a low loss in light propagation. Experimental and theoretical analysis of transmittance spectra in the UV region is done by UV–vis spectrophotometer and MATLAB based program, respectively. This technique may be used for developing several applications having excellent photocatalytic properties as well as for photonic crystal device formation.