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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.
21

Synthesis and characterization of nanostructure electrodes for lithium ion batteries. / 鋰離子電池納米電極的製備和表徵 / CUHK electronic theses & dissertations collection / Synthesis and characterization of nanostructure electrodes for lithium ion batteries. / Li li zi dian chi na mi dian ji de zhi bei he biao zheng

January 2013 (has links)
Liu, Hao = 鋰離子電池納米電極的製備和表徵 / 劉昊. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 99-103). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Liu, Hao = Li li zi dian chi na mi dian ji de zhi bei he biao zheng / Liu Hao.
22

Electrical and optoelectrical studies on nanostructured devices. / CUHK electronic theses & dissertations collection

January 2008 (has links)
Finally in combination with c-AFM and EFM, the high-k materials breakdown behaviors are also interrogated. The breakdown processes are classified into three stages: pre-breakdown (pre-BD), soft breakdown (SBD) and hard breakdown (HBD). And a HfOx nano-pattern is fabricated with the aid of AFM. The dot growth characteristics on the pulse amplitude, duration and humidity are scrutinized. / In this thesis, the single CdS nanobelt devices are fabricated successfully. The photosensitivity at 1V is up to 8 x 103 A/W and the electron mobility reaches to tens of cm/V·s. Based on these excellent optoelectronic properties, the CdS nanobelt becomes a good choice for interrogation on the charge transport characteristics on a nanometer scale. The transistor measurements show that the performance of CdS nanobelt device can be influenced by illuminations and ambient conditions, which result from the metal/CdS nanobelt contact and nanobelt surface redox reactions. / The intrinsic carrier transport characteristics in CdS nanobelt can be investigated by reconstructing of the local surface band diagram with the aid of SSPM. A ∼0.50 eV upward band bending can be obtained in the dark. The surface depletion length induced by the negative surface oxygen adsorbates is estimated to ∼66nm if a concentration of 1017 cm -3 shallow donors is assumed in the CdS nanobelt. This depletion length is close to the height of the ultra-thin CdS nanobelt. These adsorbates result in the surface depletion region expansion and the conduction channel reduction, which is responsible for the CdS conductance drop. Above the band-gap illumination or to the oxygen-deficient environment can effectively reduce the surface band bending and the depletion region, finally increase the conduction channel, which is one of the main reasons for the large photosensitivity and highly oxygen sensitivity for the single CdS nanobelt device. / To sustain Moore's law scaling trend beyond COMS, one-dimensional (1D) nanostructures, e.g. carbon nanotubes and semiconductor nanowires, are proposed to act as fundamental nanoscale blocks in the future electronic and optoelectronic devices. Therefore it is very crucial to understand the unique nature of electronic properties for 1D nanostructures in designing novel nanoelectronic devices and optimizing the device performance. In this thesis, the charge transport properties of nanostructure devices are studied. A method called photo-assisted scanning surface potential microscopy (SSPM) is developed, which yields a direct measurement of the electrostatic potential distributions across the 'biased' nanostructured device under different illumination conditions. Our efforts provide significant understanding of the nature of charge transport in nanoelectronics. / We can simply fabricate the MSM device using single CdS nanobelt. A positive Schottky barrier is found at the electrode/CdS nanobelt junction because of the unequal work function or the Fermi level pinning by the surface states. The barrier height is estimated to be 0.38 eV by fitting the temperature dependent I-V curves. A big potential drop at the junction can be visualized by SSPM. The calculated contact resistance for the electron injection is much larger than that for the CdS nanobelt, which illustrates that the transport properties of CdS nanobelt device are dominated by the charge injection process. The change in contact resistance and nanobelt resistance under the above bandgap illumination are measured by photo-assisted SSPM. The experimental results show that in the dark, the charge transport for the CdS nanobelt device is dominated by electron injection, while under high light intensity, the charge transport is governed by the intrinsic nature of CdS nanobelt. / With the aid of SPM, the charge injection and carrier transport characteristics of the individual CdS nanobelt device are systematically interrogated and comprehensively demonstrated, which are useful for designing and fabricating the nanostructured electronic and optoelectronic devices. / An, Jin. / Adviser: Jiambin Xu. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3674. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
23

Structural and electrical properties of epitaxial graphene nanoribbons

Bryan, Sarah Elizabeth 14 March 2013 (has links)
The objective of this research was to perform a systematic investigation of the unique structural and electrical properties of epitaxial graphene at the nanoscale. As the semiconductor industry faces increasing challenges in the production of integrated circuits, due to process complexity and scaling limitations, new materials research has come to the forefront of both science and engineering disciplines. Graphene, an atomically-thin sheet of carbon, was examined as a material which may replace or become integrated with silicon nanoelectronics. Specifically, this research was focused on epitaxial graphene produced on silicon carbide. This material system, as opposed to other types of graphene, holds great promise for large-scale manufacturing, and is therefore of wide interest to the academic and industrial community. In this work, high-quality epitaxial graphene production was optimized, followed by the process development necessary to fabricate epitaxial graphene nanoribbon transistors for electrical characterization. The structural and electrical transport properties of the nanoribbons were elucidated through a series of distinct experiments. First, the size-dependent conductivity of epitaxial graphene at the nanoscale was investigated. Next, the alleviation of the detrimental effects revealed during the size-dependent conductivity study was achieved through the selective functionalization of graphene with hydrogen. Finally, two techniques were developed to allow for the complementary doping of epitaxial graphene. All of the experiments presented herein reveal new and important aspects of epitaxial graphene at the nanoscale that must be considered if the material is to be adopted for use by the semiconductor industry.
24

Increased Control over Gold Colloid Adsorption on Substrates for Colloid Displacement Lithography

Sakampally, Vara Prasad Reddy 01 August 2009 (has links)
Colloid displacement lithography is proving to be very effective in the designing of nanometer scale electronic devices. Precise control of the structure of matter at the nanometer scale has brought a revolutionary change in science and technology. The use of these nanometer scale devices ranges from the diagnosis of various diseases to cell repair to ultra strong materials. This research focused on optimizing the conditions for gold colloid particle adsorption for colloid displacement lithography, an expansion on gold colloid particle manipulation techniques using a scanned probe microscope. The system consists of a scrupulously cleaned glass surface that is coated with poly(diallyldimethylammonium chloride) (PDDA) and then with 5- or 10- nm gold colloid particles. The optimum conditions include the use of very low molecular weight PDDA (Avg MW <100,000 g/mol) or low molecular weight PDDA (Avg MW 100,000-200,000 g/mol) with an exposure time to the glass substrate of 120 to 150 minutes. This is then followed by a 24-hour exposure to the colloid solution. An atomic force microscope (AFM) is used to pattern the thus prepared colloid coated slides. In this work a variety of salts are used as potential blocking agents to prevent or modify the colloid adsorption. These include potassium iodide, potassium bromide, potassium chloride, sodium fluoride, sodiumsulfate, potassium hydrogen phosphate, potassium hydrogen phthalate, and sodium citrate. In summary, the following were found as a result of this work: The optimum conditions that lead to efficient patterning are: Low molecular weight PDDA with a coating time of 120 to 150 minutes. Exposure to 5-nm gold colloid for 24 hours The most interesting potential blocking agents are the phosphate, sulfate and citrate salts, as they show some potential for modifying the adsorption of the gold colloids on the PDDA. The dispersion of the colloid particles on the PDDA does not change when using the potential blocking agents compared to direct adsorption on the unmodified PDDA layer. The use of the potential blocking agents reduces the force required to pattern by a factor of 100 to 300.
25

An investigation of nonlinear tip-sample force models for nanoindentation

Hazra, Siddharth. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 27, 2008) Includes bibliographical references.
26

A three-dimensional direct simulation Monte Carlo methodology on unstructured Delaunay grids with applications to micro and nanoflows

Chamberlin, Ryan Earl. January 2007 (has links)
Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: Nanoflow; microflow; unstructured; DSMC. Includes bibliographical references (leaves 171-178).
27

Magnetoresistive phenomena in nanoscale magnetic systems

Burton, John D. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Aug. 12, 2008). PDF text: vii, 123 p. : ill. ; 2 Mb. UMI publication number: AAT 3297588. Includes bibliographical references. Also available in microfilm and microfiche formats.
28

Stochastic energetics of the Büttiker-Landauer motor and refrigerator

Benjamin, Ronald. January 2008 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Additional advisors: Renato Camata, Nikolai Chernov, Perry A. Gerkines, Gunter Stolz. Description based on contents viewed Feb. 9, 2009; title from PDF t.p. Includes bibliographical references (p. 123-129).
29

Development of nano-characterization system for polymer film measurement and single BGA solder joint forming experiment

Reichman, Aaron Michael. January 2007 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Watson School of Engineering and Applied Science (Mechanical Engineering), 2007. / Includes bibliographical references.
30

Atomic force microscopy study of nano-confined liquids

Li, Tai-De January 2008 (has links)
Thesis (Ph.D.)--Physics, Georgia Institute of Technology, 2009. / Committee Chair: Riedo, Elisa; Committee Member: Davidovic, Dragomir; Committee Member: Goldman, Daniel I.; Committee Member: Landman, Uzi; Committee Member: Lyon, L. Andrew

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