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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

ZnO nanocones and nanoplatelets: synthesis and characterization

Chang, Yanling 12 August 2010 (has links)
Nanowire structure plays an important role in the development of nanotechnology. However, further study shows that the shape of nanowires may not be the ideal morphology for some applications such as solar cells and sensors. Thus, the purpose of this thesis is to find a low cost and high yield approach to the synthesis of other morphologies of nanostructures in order to further improve the performance of these nanodevices. To this end, a chemical approach has been extended to the synthesis ZnO nanocones and platelets. With UV illumination, the synthesis of ZnO nanocones was achieved on GaN films on sapphire and gold films on silicon substrates. Both TEM and XRD results show that as-grown ZnO nanocones are single crystals. The formation of ZnO nanocones could be explained by the absorption process of photons. The UV light induced thermal gradient modifies the heat distribution as well as the reagent transport. The chemical reaction system is kinetically limited and results in ZnO nanocones. If the UV light is blocked, the ZnO nanowires result. In addition, the density of ZnO nanocones is higher than ZnO nanowires grown without UV illumination. By this chemical approach, ZnO platelets could also be obtained on GaN films deposited by PLD, whose c-axis is parallel to the surface of the substrate. The diameters and the thickness of the platelets depend on the quality and thickness of GaN film. TEM results illustrate that the obtained ZnO platelets are single crystals grown along the <0 1 1 0> direction within the {0 0 0 1} planes. Relative growth rates of various facets were altered by the presence of [1 0 0] textured GaN film. The suppression of the growth along c axis can also be achieved by citrate anions as a structure-directing agent to adsorb selectively on ZnO basal planes. Electrical measurement shows that the resistance of ZnO platelets is about 20-40 GΩ¸ and it is higher than that of ZnO nanowires. Piezoelectric potential calculation results also indicate that the piezoelectric potential is higher than for ZnO nanowires with the same external applied stress. These procedures and results demonstrate an easy and low cost way to fabricate ZnO nanocones and platelets, which may aid the utilization of nanostructures in solar cells, sensors and other applications to further improve their performance.
192

Properties of tip-sample nanoscale structure and characterization of silicon using scanning tunneling microscopy-spectroscopy /

Lin, Hai-An. January 2000 (has links)
Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 127-134).
193

An investigation of the deformation of anodic aluminium oxide nano-honeycomb during nanoindentation /

Ng, King-yeung. January 2009 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 138-139). Also available online.
194

Adsorbate-induced nanoscale faceting of rhenium surfaces

Wang, Hao, January 2008 (has links)
Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Physics and Astronomy." Includes bibliographical references (p. 130-135).
195

Atomic force microscopy as a tool to investigate and use nanoscopic polymer interactions /

Malotky, David L., January 2001 (has links)
Thesis (Ph. D.)--Lehigh University, 2001. / Includes bibliographical references and vita.
196

Exploiting polymer single crystals to assemble and functionalize nanomaterials /

Li, Bing. Li, Christopher Yuren. January 2009 (has links)
Thesis (Ph.D.)--Drexel University, 2009. / Includes abstract and vita. Includes bibliographical references (leaves 222-238).
197

The functional roles of retinal homeobox genes in zebrafish retinal development and an introduction to silica nanomaterial toxicity in zebrafish embryos /

Nelson, Steve M. January 1900 (has links)
Thesis (Ph. D., Neuroscience)--University of Idaho, October 2009. / Major professor: Deborah L. Stenkamp. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.
198

Application of laser-based diagnostics for nanomaterials synthesis

Liu, Xiaofei, January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references.
199

Characteristics of graphitic films for carbon based magnetism and electronics

Hong, Jeongmin January 2009 (has links)
Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 19, 2010). Includes bibliographical references. Also issued in print.
200

Epoxy-clay nanocomposites : morphology, moisture absorption behavior and thermo-mechanical properties /

Hu, Chugang. January 2004 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

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