Fabrication Of Periodic Multi-configuration Metallic Nanoholes And Their SPR Effects

Surface Plasmon Resonance (SPR) can be excited and modified by periodic metallic nanohole structures. Owning to SPR, some special optical effects emerged, such as Extraordinary Optical Transmission, Surface-Enhanced Raman Scattering, Surface-enhanced Fluorescence Spectroscopy. All of these extraordinary effects can be explored on bio-chemical sensors, nano-optical and solar cells, making it possible to have the effects of optical and electrical integrated on single chip. This dissertation focuses on the fabrication process and SPR effects of periodic nanohole arrays. Subsequent research contents are included in this dissertation.1. The fabrication procedure of metallic nanohole arrays was studied. Standard MEMS process was combined with Nanosphere Lithography (NSL) in this process. By slopping the substrate in metal deposition process, the ellipse nanoholes, nanostripe structures with nanotips and nanowires were orderly developed by similar fabrication process. Some factors that affect the morphologies of the structures are analyzed. It is concluded that the nanostructure morphology can be controlled by different slopping angles in metal deposition process.2. The fabrication procedure of multi-configuration nanoholes was studied. Based on the former procedure and some further improvement, crescent nanohole arrays, hoof nanohole arrays, nanostripes with tips on single edge as well as triangular nanohole arrays were fabricated. The effects of the process on the array morphologies are studied. Also the formation of the bi-layer PS colloidal crystal and O2 ICP process are analyzed.3. The electromagnetic field distribution of periodic multi-configuration metallic nanostructure arrays was analyzed and simulated based on finite difference time domain (FDTD) method, such as the circle nanoholes, ellipse nanoholes, nanostripe structures with nanotips and nanowires. It was shown that the configuration of metal nanostructures have crucial effect on their electromagnetic field distribution. The nanostructures with high density nanotips exhibited best electromagnetic enhancement. The enhance factor reached 50. Besides, the transmission characteristic of circle nanoholes on glass substrate was analyzed.4. The optical properties of periodic nanohole structure were analyzed. Rhodamine 6G was used as probe molecules to evaluate the SERS performance of the fabricated substrates, including circle nanoholes, ellipse nanoholes, nanostripe structures with nanotips and nanowires. The resulted Raman spectra matched well with the simulation results. The nanostructures with high density nanotips exhibited the best Raman enhancement. The transmission characteristic of circle nanoholes on glass substrate was measured by spectrophotometer. The results also matched well with the simulation.