ORCID Profile
0000-0002-1438-4426
Current Organisations
University of Oxford Trinity College
,
University of Oxford
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Publisher: American Chemical Society (ACS)
Date: 05-01-2008
DOI: 10.1021/LA702701P
Abstract: A rapid route to the chemical functionalization of hydrogen-terminated diamond surfaces deposited by chemical vapor deposition involving their reaction with substituted diaryl carbenes has been investigated. To avoid difficulties in the handling of highly reactive compounds, the carbene is generated in situ from the thermal decomposition at 400 K of a thin film of the corresponding diaryl diazomethane precursor deposited at the diamond interface. X-ray photoelectron spectroscopy (XPS) has been used to verify that surface functionalization using two starting compounds, bis(4-iodophenyl) diazomethane and bis(4-nitrophenyl) diazomethane, can be achieved using this approach in agreement with recent theoretical studies. The surface grafting density is measured to be around 10(14) cm(-2) in each case. The chemistry observed is found to be insensitive to the detailed properties of the diamond film and to the presence of oxygen contamination at the hydrogen-terminated diamond surface. We further demonstrate the utility of the approach, in the case of the bound nitrophenyl compound, by its reduction to the corresponding primary amine followed by reaction with fluorescein isothiocyanate to achieve fluorescent tagging of the diamond interface.
Publisher: American Physical Society (APS)
Date: 29-05-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B914733K
Abstract: A range of sol-gel synthesis conditions were used to prepare high surface area N-doped TiO(2) in the anatase phase. The N dopant was derived either from NH(3) in solution or from NH(3) gas bubbled through solution. Bulk N doping levels were determined by an inert gas fusion method and were compared with surface N doping levels determined by X-ray photoelectron spectroscopy. Comparison was also made with the concentration of paramagnetic species measured by electron spin resonance spectroscopy. It was found that both surface and bulk doping levels were typically around 3 orders of magnitude higher than the concentration of paramagnetic N-containing species. All N-doped s les showed higher visible region (lambda > 395 nm) photocatalytic activity than undoped anatase itself. It is argued that catalytic activity is associated with the presence of nitrogen bound to lattice oxygen to give (NO)'O which can be photoexcited to give (NO)(O)(X).
Publisher: American Physical Society (APS)
Date: 11-09-2008
Publisher: American Chemical Society (ACS)
Date: 09-2009
DOI: 10.1021/CM901127R
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B719364E
Publisher: American Physical Society (APS)
Date: 15-01-2014
Publisher: AIP Publishing
Date: 07-2009
DOI: 10.1063/1.3153966
Abstract: The influence of Sn doping on the growth of In2O3 on Y-stabilized ZrO2(100) by oxygen plasma assisted molecular beam epitaxy has been investigated over a range of substrate temperatures between 650 and 900 °C. The extent of dopant incorporation under a constant Sn flux decreases monotonically with increasing substrate temperature, although the n-type carrier concentration in “overdoped” films grown at 650 °C is lower than in films with a lower Sn concentration grown at 750 °C. The small increase in lattice parameter associated with Sn doping leads to improved matching with the substrate and suppresses breakup of the films into square islands observed in high temperature growth of undoped In2O3 on Y-stabilized ZrO2(100). Plasmon energies derived from infrared reflection spectra of Sn-doped films are found to be close to satellite energies in core level photoemission spectroscopy, but for a nominally undoped reference s le there is evidence for carrier accumulation at the surface. This influences both the In 3d core line shape and the intensity of a peak close to the Fermi energy associated with photoemission from the conduction band.
Publisher: American Physical Society (APS)
Date: 03-04-2018
Publisher: American Chemical Society (ACS)
Date: 24-12-2018
Publisher: IOP Publishing
Date: 03-08-2011
DOI: 10.1088/0953-8984/23/33/334211
Abstract: Epitaxial films of In(2)O(3) have been grown on Y-stabilised ZrO(2)(111) substrates by molecular beam epitaxy over a range of thicknesses between 35 and 420 nm. The thinnest films are strained, but display a 'cross-hatch' morphology associated with a network of misfit dislocations which allow partial accommodation of the lattice mismatch. With increasing thickness a 'dewetting' process occurs and the films break up into micron sized mesas, which coalesce into continuous films at the highest coverages. The changes in morphology are accompanied by a progressive release of strain and an increase in carrier mobility to a maximum value of 73 cm(2) V(-1) s(-1). The optical band gap in strained ultrathin films is found to be smaller than for thicker films. Modelling of the system, using a combination of classical pair-wise potentials and ab initio density functional theory, provides a microscopic description of the elastic contributions to the strained epitaxial growth, as well as the electronic effects that give rise to the observed band gap changes. The band gap increase induced by the uniaxial compression is offset by the band gap reduction associated with the epitaxial tensile strain.
Publisher: American Physical Society (APS)
Date: 11-04-2014
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Russell George Egdell.