Date of Graduation
Bachelor of Science in Mechanical Engineering
Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from the introduction of the Au thin-film microstructure in the electrode structure was greater. The experimental device enhancement found for the introduction of the thin-film microstructures is most likely attributed to hot electron excitation. This computational study will simulate the optical properties of these two devices in order to determine what plasmonic properties and optical enhancement these devices may have. The modeling software used to validate the experimental results solved Maxwell’s equations with a finite element method (FEM) mathematical algorithm provided by COMSOL Multiphysics. For the interdigital photodetectors device, it was determined that the device response as a function of electrode gap and incident light polarization angle were similar to the experimental results. The enhancement provided by the introduction of the Au thin-film microstructures cannot be completely explained by plasmonic activity occurring with the microstructures, but there is plasmonic activity occurring with the devices.
Hill, Avery M., "Optical Analysis and Fabrication of Micro and Nanoscale Plasmonically Enhanced Devices" (2016). Mechanical Engineering Undergraduate Honors Theses. 52.