High efficiency solution infiltration routes to thin films with photonic properties

A chemical bath deposition (CBD) method has been developed to prepare three-dimensionally-ordered macroporous films of CdS and TiO₂, using colloidal crystals as templates. A series of sequential, short infill/rinse/anneal steps are employed to effect complete infiltration of SiO₂ (opal) thin films with CdS or TiO₂. Removal of templates allows fabrication of macroporous inverse replica structures that exhibit periodic modulation of dielectric behaviour and have potential for use in photonic applications. A study of the photonic properties of films indicates that the multi-step CBD method is a useful approach for infiltration of opal interstices.