Fig. 2.
Layer periodicity dictates the location of the photonic stopband. (A) If the superlattice is viewed as alternating layers that do and do not contain the NPs, then the layer periodicity is defined as the spacing between two adjacent layers that contain NPs. (B and C) Dependence of (B) maximum reflectance (Rmax) and (C) its corresponding wavelength (λpeak) on the layer periodicity of cP, cI, and cF superlattices. (D and E) Dependence of (D) Rmax and (E) center wavelength (λ0) on the layer periodicity for tP and tI lattices. The lattice constant within each layer is kept constant at 200 nm. Only the λ values of a reflectance larger than 0.9 are considered as the stopband, and its λ0 is plotted as a function of layer periodicity in E.