Surface Modification, Fabrication, and Characterization of Silicon, Polymer, and Nanotube Composite Materials

• Main Author: Pei, Lei
• Format: Others
• Published: BYU ScholarsArchive 2011
• Subjects: surface modification; fabrication; characterization; carbon nanotube; silicon; polymer composite; Biochemistry; Chemistry
• Online Access: https://scholarsarchive.byu.edu/etd/2925; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3924&context=etd

In my research, I have performed many characterization and fabrication experiments that are based on tools of analytical chemistry, materials chemistry, and surface science. My research projects are as follows. (1) Fabrication of transparent polymer templates for nanostructured amorphous silicon photovoltaics was done using low-cost nanoimprint lithography of polydimethylsiloxane. This approach provides a test bed for absorption studies in nanostructured film geometries and should result in improved light capturing designs in thin-film solar cells. Nanopatterned polymer films were characterized by scanning electron microscopy and optical measurements. (2) A straightforward method for fabricating freely suspended, thin, carbon nanotube (CNT) membranes infiltrated with polymers was developed. This process is a new approach for making thin, reinforced, smooth films or membranes with high concentrations of CNTs, which may lead to higher performance materials. Characterization of the film and membrane was performed via scanning electron microscopy and atomic force microscopy. (3) Laser activation-modification of semiconductor surfaces (LAMSS) was carried out on silicon with a series of 1-alkenes. A key finding from this study is that the degree of surface functionalization in a LAMSS spot appears to decrease radially from the center of the spot. These laser spots were studied by time of flight secondary ion mass spectrometry (ToF-SIMS), and the resulting spectra were analyzed using a series of chemometrics methods. (4) A large ToF-SIMS data set from multiple coal samples spanning a wide range of coal properties was subjected to a chemometrics analysis. This analysis separates the spectra into clusters that correspond to measurements from classical combustion analyses. Thus ToF-SIMS appears to be a promising technique for analysis of this important fuel. (5) Several experiments on carbon nanotube processing were performed in my research, including carbon nanotube sheet formation, carbon nanotube purification, carbon nanotube dispersion, and carbon nanotube functionalization. X-ray photoelectron spectroscopy was a key characterization tool for many of these experiments.