Physics (Theses and Dissertations): Recent submissions
Now showing items 161-180 of 458
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Transformations of Guassian laser beams via conical diffraction : theory, experiment and applications
(Trinity College (Dublin, Ireland). School of Physics, 2011)The work reported in this thesis concerns the shaping of Gaussian laser beams using conical diffraction. Conical diffraction is the extension to wave optics of internal conical refraction, in which a ray of light incident ... -
Atomistic models and time-dependent simulations of spin dynamics in isolated and current-carrying systems
(Trinity College (Dublin, Ireland). School of Physics, 2012)Understanding and ultimately controlling the dynamics of electrons and their spins is an important aspect of spin-based electronics. Recent experimental advances open up new possibilities for probing spin dynamics with ... -
Electronic transport on carbon nanotube networks : a multiscale computational approach
(Trinity College (Dublin, Ireland). School of Physics, 2011)Carbon is arguably the most versatile of chemical elements. For the last 25 years research on carbon nanostrutures has been one of the most active areas of science. Carbon-based nanoelectronics is the most promising ... -
Investigation of electronic structure and optical properties of organic molecular semiconductor materials by X-ray spectroscopies
(Trinity College (Dublin, Ireland). School of Physics, 2009)The electronic structure of thin films of several members of the metal phthalocyanine (MPc) and metal chelate families of organic molecular semiconductors have been studied using resonant soft x-ray emission spectroscopy, ... -
Electro-magnetic control of laser produced plasma
(Trinity College (Dublin, Ireland). School of Physics, 2011)This thesis describes the results of experiments to investigate the effects of magnetic and electric fields on the expansion dynamics of a low temperature laser produced plasma. The experiments were done in vacuum using ... -
Transparent conducting oxide based devices
(Trinity College (Dublin, Ireland). School of Physics, 2011)Transparent conducting oxide (TCO) materials, formerly regarded as degenerate conductors of only one carrier type, can now be considered as transparent semiconductors possessing the potential for integration into more ... -
Spin transfer torque magnetisation switching in MgO based magnetic tunnel junctions
(Trinity College (Dublin, Ireland). School of Physics, 2010)Magnetic tunnel junctions (MTJ) are important magnetic elements that are used as memory and sensor devices. In this thesis, first, the fundamentals of MTJs were explored by investigating different tunnel barrier materials, ... -
An experimental investigation into the conversion of optical spin to orbital angular momentum using internal conical diffraction
(Trinity College (Dublin, Ireland). School of Physics, 2010)Internal conical refraction (ICR) transforms a ray incident upon the optic axis of a biaxial crystal into a cone of light within the medium and a hollow cylinder of light upon exiting. If the incident ray is circularly ... -
Two-photon absorption based detection in semiconductor microcavities
(Trinity College (Dublin, Ireland). School of Physics, 2009)The most important feature of a two-photon absorption microcavity (TPAM) is that of its enhancement of the optical field which enhances the level of twophoton absorption (TPA) for a particular input optical power incident ... -
Optical properties and photoluminescence quantum yields of carbon nanotube dispersions
(Trinity College (Dublin, Ireland). School of Physics, 2011)The absorbance and photoluminescence (PL) spectra of single-walled carbon nanotubes (SWNTs) dispersed in deuterium oxide (D2O) using various surfactants were examined in order to estimate the photoluminescence quantum yield ... -
Anisotropic magneto-transport properties of epitaxial magnetite thin films
(Trinity College (Dublin, Ireland). School of Physics, 2010)In this thesis we investigate the anisotropic magneto-transport properties of epitaxial Fe304 films grown on MgO substrates. In particular we investigate the angular dependence of the anisotropic niagnetoresistance (AMR), ... -
Impurities and magnetic interactions in graphene : a theoretical study
(Trinity College (Dublin, Ireland). School of Physics, 2012)Graphene is a two-dimensional carbon material that until its recent discovery was assumed not to exist in the free state. Graphene-related materials have been in the scientific limelight since then due to several key ... -
Controlled electromigration on vicinal surfaces
(Trinity College (Dublin, Ireland). School of Physics, 2012)The influence of an electric field on the dynamics of steps, on vicinal surfaces, during high temperature annealing was experimentally studied. An experimental setup was designed, constructed and employed to explicitly ... -
Selective gene fishing in complex genomic environments using micro-cantilevers : applications in RNAi therapy
(Trinity College (Dublin, Ireland). School of Physics, 2012)Genes and their role in disease origins and proliferation have been of great interest for molecular medicine. Their functions and roles have been recently shown to be moderated by RNA interference (RNAi), a natural phenomenon ... -
Investigation of nanosecond and femtosecond pulsed laser deposition and application of some metal nanoparticle films
(Trinity College (Dublin, Ireland). School of Physics, 2012)Pulsed laser deposition (PLD) is a convenient and flexible technique which can be applied to all elemental and compound solids. In conventional PLD a nanosecond (ns) laser is used to ablate the surface of a solid target ... -
The structure of monodisperse foam
(Trinity College (Dublin, Ireland). School of Physics, 2012)Equal-sized bubbles of average diameter less than one millimetre are found to spontaneously crystallise upon formation. While previously employed by Sir Laurence Bragg as an ideal system with which to study crystalline ... -
Charging, doping and gating of a single dangling bond on a bare Si(100)-c(4x2) surface
(Trinity College (Dublin, Ireland). School of Physics, 2012)Despite the increasing interest in novel materials for the next generation of microelectronic devices, such as graphene and topological insulators, Si(100) surface is still the most important substrate for nano-device ... -
Highly conductive, transparent and flexible networks of quasi 1-Dimensional metallic nanostructures
(Trinity College (Dublin, Ireland). School of Physics, 2011)Direct current conductivity and morphological characterization has been performed on a wide range of films made from bundled single wall carbon nanotubes, produced by a selection of commercial suppliers. The conductivity ... -
Noise controlled semiconductor optical amplifiers
(Trinity College (Dublin, Ireland). School of Physics, 2012)Semiconductor optical amplifiers (SOA) have been widely used in communications systems for decades, in a multitude of capacities. In their simplest form SOAs offer cost effective linear amplification at a variety of ... -
Growth and electrical characterisation of conjugated polymer nanostructures
(Trinity College (Dublin, Ireland). School of Physics, 2011)The field of conductive polymers is one in which there has been much interest in the last number of years. Two of the most common conductive polymers, polypyrrole and poly(p-phenylene vinylene) are investigated in the ...
