Browsing School of Physics by Sponsor "Higher Education Authority (HEA)"
Now showing items 1-20 of 22
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Alternating and direct current characterization and photoinduced absorption studies of modified conjugated polymer thin films
(2004)Control of interchain separation enables the optical properties of polymer thin films to be altered. We present a thin film preparation technique that increases the free volume fraction in spin coated polymer thin films ... -
Band structures of rare gas solids within the GW approximation
(2005)Band structures for solid rare gases s Ne, Ar d have been calculated using the GW approximation. All electron and pseudopotential ab initio calculations were performed using Gaussian orbital basis sets and the ... -
Comparative Imaging Study in Ultrasound, MRI, CT and DSA using a Multi-Modality Renal Artery Phantom
(2011)Purpose: A range of anatomically-realistic multi-modality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal ... -
Conducting mechanism in the epitaxial p-type transparent conducting oxide Cr2O3:Mg
(2015)Epitaxial p -type transparent conducting oxide (TCO) Cr 2 O 3 :Mg was grown by electron-beam evaporation in a molecular beam epitaxy system on c -plane sapphire. The influence of Mg dopants and the oxygen partial ... -
Electronic Structure and Lattice Vibrations of Ca2CuO2Cl2: a hybrid density functional study
(2008)The electronic structure and phonon modes of Ca 2 CuO 2 Cl 2 have been calculated using hybrid density functional theory HDFT methods. The material is correctly predicted to be an antiferromagnetic insulator with ... -
Enhanced brightness in organic light-emitting diodes using a carbon nanotube composite as an electron-transport layer
(2001)We have studied the effects of using a composite fabricated from carbon nanotubes and a host polymer, poly(m-phenylene-vinylene-co-2,5-dioctyloxy-p-phenylene-vinylene) (PmPV), as an electron-transport layer in organic ... -
Experimental observation of scaling laws for alternating current and direct current conductivity in polymer-carbon nanotube composite thin films
(2002)Alternating current (ac) and direct current (dc) conductivities have been measured in polymer-nanotube composite thin films. This was carried out for a range of concentrations of multiwall nanotubes in two polymer hosts, ... -
Friedel Oscillations in graphene: Sublattice Asymmetry in Doping
(2013)Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent ... -
Hydrogen evolution across nano-Schottky junctions at carbon supported MoS 2 catalysts in biphasic liquid systems
(2012)The activities of a series of MoS 2-based hydrogen evolution catalysts were studied by biphasic reactions monitored by UV/Vis spectroscopy. Carbon supported MoS 2 catalysts performed best due to an abundance of catalytic ... -
Impact of bias current distribution on the noise figure and power saturation of a multicontact semiconductor optical amplifier
(2011)We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is ... -
Improving the Mechanical Properties of Single-Walled Carbon Nanotube Sheets by Intercalation of Polymeric Adhesives
(2003)Organic polymers, such as poly(vinyl alcohol), poly(vinyl pyrrolidone), and poly(styrene), were intercalated into single-walled carbon nanotube sheets by soaking the sheets in polymer solutions. Even for short soak times, ... -
Interaction of surface plasmons with CdTe quantum dot excitons
(SPIE, 2005)A 5-fold enhancement in the luminescence of CdTe nanocrystal quantum dots (QDs) is observed when they are placed in proximity to a nanostructured Au film deposited by pulsed laser deposition technique. No enhancement is ... -
Magnetic and electronic properties of D022-Mn3Ge (001) films
(2012)Oriented thin films of Mn3Ge with the tetragonal D022structure,grown on strontium titanate substrates, exhibit a low magnetization M s?=?73?kA m?1 combined with high uniaxial anisotropyK u?=?0.91?MJ m?3 at 300?K, making ... -
Measurement of nanotube content in pyrolytically generated carbon soot
(2000)Carbon nanotubes can be efficiently separated from impurity material in carbon soot using a conjugated polymer filtration system as monitored by EPR, allowing the calculation of purity of the crude carbon soot. -
Nitrogen assisted etching of graphene layers in a scanning electron microscope
(2011)We describe the controlled patterning of nanopores in graphene layers by using the low-energy (<10?keV) focused electron beam in a scanning electron microscope. Regular nanometer-sized holes can be fabricated with the ... -
Reflectance anisotropy spectroscopy of Si(111)-(3×1)Li and Ag surfaces
(2013)The Si(111)-(3?1)Li and Ag surface structures consist of Si honeycomb chains separated by channels occupied by Li or Ag atoms. The dimerization of neighboring Ag atoms results in a larger c(12?2)Ag superstructure. We report ... -
Role of defects in ferromagnetism in Zn1-xCoxO: A hybrid density functional study
(2006)Experimental studies of Zn1−xCoxO as thin films or nanocrystals have found ferromagnetism and Curie temperatures above room temperature and that p- or n-type doping of Zn1−xCoxO can change its magnetic state. Bulk Zn1−xCoxO ... -
Small polarons and magnetic anti-phase boundaries in Ca2−xNaxCuO2Cl2 (x=0.06,0.12): origin of striped phases in cuprates
(2008)We report hybrid density functional theory calculations on hole doped Ca2−xNaxCuO2Cl2 performed in 4×4, 4√2×4√2, and 8×2 supercells with hole concentrations x=0.0625 and x=0.125. Holes at the lower concentration form small ... -
Spin polaron effective magnetic model for La0.5Ca0.5MnO3
(2004)The conventional paradigm of charge order for La1−xCaxMnO3 for x=0.5 has been challenged recently by a Zener polaron picture emerging from experiments and theoretical calculations. The effective low energy Hamiltonian for ...