Nanoscience and Nanotechnology Commons^™

Kinetics Of Length Scale Dependent Deformation Of Gold Microspheres And Micropillars, A Z M Ariful Islam

Electronic Thesis and Dissertation Repository

In this thesis length and time scale dependence of the operative plastic deformation mechanisms in Au is studied. Uniaxial compression tests were performed at various loading rates on FIB-milled Au micropillars and single-crystalline Au microspheres of diameter ranging from 0.8 to 6.0 µm to investigate the incipient and bulk plasticity events. Constant-load ambient-temperature creep tests were performed on the micropillars to study the time-dependent plasticity at very slow strain rates. Uniaxial compression tests were also performed on coated Au microspheres to study the effect of extrinsic constraint on the deformation mechanisms.

During uniaxial compression, both the Au micropillars and microspheres …

Doped Tio2 Nanowires For Applications In Dye Sensitized Solar Cells And Sacrifical Hydrogen Production, Qasem Alsharari

Electronic Thesis and Dissertation Repository

This thesis explores the synthesis of metal oxide 1-D nanowires using a sol-gel method in supercritical carbon dioxide (sc-CO₂), as an environmental friendly enabling solvent. Porous nanowires were synthesized and their performance was tested in dye sensitized solar cell and sacrifical hydrogen production. Titanium isopropoxide (TIP) was used as a precursor for titania synthesis while copper, bismuth and indium were examined as dopants, respectively. The sol-gel reactions were catalyzed by acetic acid in CO₂ at a temperature of 60 °C and pressure of 5000 psi. It was observed that acetic acid/monomer ratio > 4 produced nanowires while a …

Size-Dependent Electroelastic Properties Of Piezoelectric Nanoplates, Zhengrong Zhang

Electronic Thesis and Dissertation Repository

With the development of nanotechnology, piezoelectric nanostructures have attracted a surge of interests in research communities for the potential applications as transistors, sensors, actuators, resonators and energy harvesters in nanoelectromechanical systems (NEMS) due to their high electromechanical coupling and unique features at the nano-scale. Piezoelectric nanomaterials have been characterized to possess size-dependent electromechanical coupling properties from both experimental and theoretical perspectives. Therefore it is of great importance to investigate the physical mechanisms of these distinct nano-scale structure features in order to fulfill the design and application of those piezoelectricity-based nanodevices.

Due to large surface to volume ratio and manifest strain …

Vibration And Buckling Of Carbon Nanotube, Graphene, And Nanowire, Mohammad Hadi Mahdavi

Electronic Thesis and Dissertation Repository

Nanostructured materials with superior physical properties hold promise for the development of novel nanodevices. Full potential applications of such advanced materials require accurate characterization of their physical properties, which in turn necessitates the development of computer-based simulations along with novel experimental techniques. Since controlled experiments are difficult for nanoscale materials and atomic studies are computationally expensive, continuum mechanics-based simulations of nanomaterials and nanostructures have become the focal points of computational nano-science and materials modelling.

In this study, emphasis is given to predicting the mechanical behaviour of carbon nanotube (CNT), graphene, nanowire (NW), and nanowire encapsulated in carbon nanotube (NW@CNT), which …

Electronic And Magnetic Excitations In Graphene And Magnetic Nano-Ribbons, Maher Zakaria Ahmed Selim

Electronic Thesis and Dissertation Repository

The discovery of graphene - a 2D material with superior physical properties - in 2004 was important for the intensive global research to find alternatives to three-dimensional (3D) semiconductor materials in industry. At the same time there have been exciting advances for 2D magnetic materials on the nanometer scale. The superior properties of graphene are mainly attributed to its crystal structure and its relatively short-range interactions. These properties show that natural and artificial 2D materials are promising for new applications.

In this thesis we have carried out a comprehensive investigation of the effects of the 2D lattice structures, the roles …