Fabrication of colloidal photonic crystals by a micro-cell based on Al thin film

Colloidal photonic crystals were synthesized by a forced deposition method. A new micro-cell was developed through thermal deposition and micro-mechanical score, by replacing conventional photosensitive resin with Al thin film and polyether-sulfone membrane. The Al film thickness Could control the sphere size, and the polyether-sulfone membrane thickness could control the layers of colloidal photonic crystals. Monodispersed colloidal polystyrene spheres with different sizes were used to deposit the colloidal photonic crystals in the micro-cell to confirm the validity of this method. SEM patterns and transmission spectra show that the crystals exhibit a face-centered cubic structure with low defect density, and the band gap agrees with the calculated result very well. Furthermore, a drying process Could influence the shape of the polystyrene spheres, resulting in a blue shift of the photonic band gap.