Fabrication of two-dimensional hybrid photonic crystals utilizing electron beam lithography

A step-by-step description of a process for a reproducible fabrication of two-dimensional hybrid photonic crystals utilizing electron beam lithography and subsequent lift-off technique is presented. The devices consist of a periodic array of gold nanodots of (100 × 100) μm2 up to (400 × 400) μm2 in size on a dielectric layer as slab-waveguide. Arrays were fabricated on indium tin oxide, silicon oxynitride and tungsten oxide with dot diameters from 70 to 550 nm, respectively. Patterning is performed by electron beam lithography using the single pixel line writing mode. Dot sizes are achieved by overexposure and overdevelopment. For dots with diameters over 250 nm, a controlled defocused beam is used for exposure. Homogeneity of the dot shape over the array is achieved by refocusing prior to exposure and using a 10-μm aperture for larger depth of field. Metallization adhesion problems can be solved by introducing a plasma clean prior to deposition. Fabricated devices were characterized in extinction measurements, showing clear correlations between dot shape and particle-plasmon spectral width.