Optical and Electro-Optical Characterization of Hybrid Metal-Semiconductor Hybrid Metamaterials

Mesoscale polyhedron-like structures, hereon referred to as mesopyramids, are formed by annealing an ~30 nm thick Au film supported on Si(100) in vacuo to approximately 750 ^oC. The base of the mesopyramids is typically on the order of tens of microns and the height 3-5 mm. Their surface topography consists of channels and plateaus that are 100-200 nm across and tens of microns in length, which is ideal for the launching and propagation of surface plasmon polaritons (SPP). It is proposed that SPP scattering can be exploited for electro-optic coupling. The SPP activity of the mesopyramids is examined using confocal microscopy, where the mesopyramids are coated with ZnO and GaN to create electro-optic devices. Electrical current is passed through the semiconductor layer while simultaneously acquiring visible light reflectivity spectra from the mesopyramids. The reflectivity spectrum experiences a blue shift proportional to the applied voltage/current. The blue shift is attributed to polarization of the semiconductor layer, i.e. a change the materials dielectric response function.