CdSe/CdS nanocrystals coupled to a self-assembled plasmonic crystal

We report here the fabrication of gold surfaces with a two-dimensional periodic corrugation by taking advantage of inexpensive self-assembly techniques. We use silica opals as a template for the 2D pattern. Opals are 3D photonic crystals obtained by self-assembly of dielectric nano-spheres. An optically thick gold layer is evaporated onto the surface of the opal to create a periodically corrugated plasmonic surface with a triangular lattice. Fig. 1 presents the surface of such a structure, good crystalline order is obtained for distances as long as 10 μm. An additional layer of silica is sputtered on top of the gold so that nanocrystals are not quenched on the metallic surface. The samples are optically characterized by angleand polarization-resolved specular reflectivity. Dips are evidenced in the p-polarized reflection spectra with an angle dependence, attributed to excitation of the surface plasmon polariton mode. These systems are very versatile as the plasmon energy can be tuned by adjusting the gold evaporation parameters.