Nano-Materials for Microwave and Terahertz Applications

Publication Year:
2015
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Downloads 55
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Repository URL:
https://corescholar.libraries.wright.edu/etd_all/1599
Author(s):
Myers, Joshua
Tags:
Ph.D. In Engineering; Scanning Microwave Microscope; Graphene; 2D Materials; AFM; Plasmonics; THz; Photonics; Defects; Nano-Materials; Spin-Spray; Ferrite; Engineering; Ph.D. In Engineering; Scanning Microwave Microscope; Graphene; 2D Materials; AFM; Plasmonics; THz; Photonics; Defects; Nano-Materials; Spin-Spray; Ferrite
thesis / dissertation description
In this age of digital electronics the quest for faster computational devices and high speed communications have driven a need for new materials that are capable of fulfilling these goals. In both areas the need for a thinner channel in transistors, faster carrier transport characteristics, and better magnetic materials dominate the direction of research. Recently 2D materials have been realized. These single layer atomic thick materials show potential in having extremely high carrier transport velocities at room temperature and, due to their natural 2D structure, are the thinnest material possible in nature. On the other hand spin-spray ferrites have showed potential in producing high permeability, low loss materials with a low processing temperature compatible with current CMOS technology. One of the largest hindrances in the implementation of these materials are the lack of measurement capabilities. Both 2D materials and spin-spray ferrites have nm sized features that significantly change how the material behave. To further investigate these materials scanning microwave microscopy (SMM) is being developed as a possible characterization tool. SMM has the unique ability to collect the complex reflection coefficient simultaneously with the topography at nm horizontal spatial resolutions. The complex reflection coefficient is able to supply valuable information about materials such as conductivity and permittivity. This dissertation provides an in depth look at the potential applications for SMM and supplies a rigorous characterization, both experimentally and numerical simulations, of the SMM system. In detail we re- port first time SMM measurements of graphene's conductivity and permittivity along with characterization of graphene defects induced by oxygen plasma etching and graphene wrinkles. We have also experimentally show conductive grain boundaries in spin-spray ferrites leading to larger than expected losses. Lastly we show Fourier transform inferred spectroscopy measurements of graphene micro and nano ribbons. These results show the versatility of SMM and the ability to further characterize new materials. Furthermore we show the ability of the SMM to obtain calibrated conductivity and permittivity measurements on the nanoscale level leading to a more complete understanding of the effects of defects on the electrical properties of graphene and understanding of the losses in ferrimagnetic materials.