Year of Publication

2007

Document Type

Thesis

College

Engineering

Department

Electrical Engineering

First Advisor

Ingrid St. Omer

Abstract

Cubic-phase silicon carbide (andamp;acirc;-SiC) nanostructures were successfully synthesized by the reaction of silicon monoxide (SiO) powder with multi-walled carbon nanotubes (MWCNTs) at high temperatures. Experiments were conducted under vacuum or in the presence of argon gas in a high-temperature furnace and the fabrication parameters of temperature (1300 -1500andamp;deg;C), time, and reactant material mass were varied to optimize the material. The resulting samples were then physically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analysis revealed the presence of dominant andamp;acirc;-silicon carbide phases. SEM images depicted morphologies similar to the starting MWCNTs, having relatively larger diameter sizes, shorter lengths and reduced curvature. TEM observations showed the presence of solid and hollow nanostructures with both crystalline and amorphous regions. Additional experiments were performed to investigate de-aggregation and dispersion procedures for the andamp;acirc;-SiC nanostructures fabricated. Optimum results for these experiments were achieved by ultrasonication of 0.01 wt.% andamp;acirc;-SiC in N,N dimethyl formamide (DMF) and dispersion using a spin coater. A methodology for electrical testing of andamp;acirc;-SiC nanostructures was developed using the de-aggregation and dispersion process established. SEM observations revealed that the random nature of the dispersion procedure used was not efficient in forming contacts regions that would allow electrical measurements of andamp;acirc;-SiC nanostructures on the pre-patterned silicon substrate.

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