Focused ion beam nanomachining and nanopatterning for optical structure fabrication

• Main Author: Wang, Houxiao
• Other Authors: Zhou Wei
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/51182
• Institution: Nanyang Technological University

With the development of the nano-precision facilities and technologies, more interest has been gained to develop functional bio-inspired materials and devices as well as the plasmonic devices due to their promising potential for various applications, among which the nanoscale optical structures have gained much more attention for the applications in the fields of photonics, electronics, sensing, biology, and solar cells, etc. An important technical focus on these areas is the selection of appropriate mirco- or nano-scale tools and techniques for various applications. Focused ion beam (FIB) has its strength in one-step maskless simpler, more flexible, and better-controlled nano-precision machining, patterning and fabrication especially for submicron or nanoscale various functional samples or structures. Besides, another advantage of FIB is that it can be conveniently used to machine the biology to analyze its structures, and FIB nanopatterning can be further used to fabricate the designed nanostructures inspired by the observed biostructures. Moreover, another important interest regarding the development of plasmonic structures is how to make them precisely designed and fabricated using the existing simulation and nanofabrication techniques and facilities. Accordingly, this investigation primarily aims to develop various functional bio-inspired and plasmonic optical structures mainly using FIB and finite difference time domain (FDTD) computation method based on the structural analyses for human hairs and butterfly wings to decipher their structural colors as well as the FIB-assisted interface endpoint detection. It was found that the loss of pigments during hair whitening resulted in obvious changes of the inner hair structure, causing a synthetic chain reaction of the optical effect as a result of the change of hair color. Commonly, butterfly wings were covered by lots of pigmented and structured micro scales for coloration, which imbricately arrayed and overlapped one another. Besides, the structures in different-colored locations of the observed butterfly wings differed obviously, and the observed structures could account for the different colors on the butterfly wings.