A5080071978- Surface and Thin Film Phenomena
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Advanced Chemical Physics Studies
- Porphyrin and Phthalocyanine Chemistry
- Graphene research and applications
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Atomic and Molecular Physics
- Semiconductor materials and interfaces
- Mass Spectrometry Techniques and Applications
- Organic Electronics and Photovoltaics
- Photocathodes and Microchannel Plates
- Copper Interconnects and Reliability
- Quantum and electron transport phenomena
- Chemical and Physical Properties of Materials
- Force Microscopy Techniques and Applications
- Electronic Packaging and Soldering Technologies
- Physics of Superconductivity and Magnetism
- Chalcogenide Semiconductor Thin Films
- Integrated Circuits and Semiconductor Failure Analysis
- Graphene and Nanomaterials Applications
- Carbon Nanotubes in Composites
- Superconductivity in MgB2 and Alloys
Dublin City University
2010-2024
22q11 Ireland
2015
Trinity College
2014
University College Cork
2010
Trinity College Dublin
1975-2008
Cardiff University
1992-1996
University of Wales
1991-1994
University of Manchester
1988-1991
A surface sensitivity study was performed on different transition-metal dichalcogenides (TMDs) under ambient conditions in order to understand which material is the most suitable for future device applications. Initially, Atomic Force Microscopy and Scanning Electron studies were carried out over a period of 27 days mechanically exfoliated flakes 5 TMDs, namely, MoS2, MoSe2, MoTe2, HfS2, HfSe2. The reactive MoTe2 HfSe2, particular, showed protrusions after exposure, reaching height width...
Bottom-up strategies can be effectively implemented for the fabrication of atomically precise graphene nanoribbons. Recently, using 10,10′-dibromo-9,9′-bianthracene (DBBA) as a molecular precursor to grow armchair nanoribbons on Au(111) and Cu(111), we have shown that substrate activity considerably affects dynamics ribbon formation, nonetheless without significant modifications in growth mechanism. In this paper compare on-surface reaction pathways DBBA molecules Cu(111) Cu(110). Evolution...
Atomically precise graphene nanoribbons (GNRs) can be fabricated via thermally induced polymerization of halogen containing molecular precursors on metal surfaces. In this paper the effect substrate reactivity growth and structure armchair GNRs (AGNRs) grown inert Au(111) active Cu(111) surfaces has been systematically studied by a combination core-level X-ray spectroscopies scanning tunneling microscopy. It is demonstrated that activation threshold for dehalogenation process decreases with...
A combination of normal-incidence x-ray standing-wave (NIXSW) spectroscopy, photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and density-functional theory (DFT) has been used to investigate the interaction a number phthalocyanine molecules (specifically, SnPc, PbPc, CoPc) with Ag(111) surface. The metal-surface distances predicted by DFT calculations for SnPc/Ag(111) $(2.48\text{ }\text{\AA{}})$ CoPc/Ag(111) $(2.88\text{ are in good agreement our NIXSW experimental...
Oxygen binding and cleavage are important for both molecular recognition catalysis. Mn-based porphyrins in particular used as catalysts the epoxidation of alkenes, this study homolytic O2 by a surface-supported monolayer Mn on Ag(111) is demonstrated scanning tunneling microscopy, X-ray absorption, photoemission. As deposited, {5,10,15,20-tetraphenylporphyrinato}Mn(III)Cl (MnClTPP) adopts saddle conformation with average plane its macrocycle parallel to substrate axial Cl ligand pointing...
A study of the adsorption sulfur on GaAs(100) surface after in situ thermal desorption a protective As capping layer is presented. The flux was generated by decomposition silver sulfide an UHV-compatible electrochemical cell. Use As-capped samples provided means to interaction with both c(2\ifmmode\times\else\texttimes\fi{}8) and (4\ifmmode\times\else\texttimes\fi{}1) reconstructions. Scanning-tunneling-microscopy images sulfur-covered indicated formation disordered layers which display...
We investigate the bottom-up growth of N = 7 armchair graphene nanoribbons (7-AGNRs) from 10,10'-dibromo-9,9'-bianthracene (DBBA) molecules on Ag(111) with focus role organometallic (OM) intermediates. It is demonstrated that DBBA are partially debrominated at room temperature and lose all bromine atoms elevated temperatures. Similar to Cu(111), form OM chains Ag(111). Nevertheless, in contrast Cu(111) substrate, formation polyanthracene intermediates via an Ullmann-type reaction feasible...
The formation of hexagonal boron nitride $(h\text{\ensuremath{-}}\mathrm{B}\mathrm{N})$ monolayers on Ni(111), Rh(111), and Pt(111) has been studied by a combination x-ray emission, angle-resolved valence band photoemission, absorption in search for interface-induced gap states $h\text{\ensuremath{-}}\mathrm{B}\mathrm{N}$. A significant density both occupied unoccupied with $\mathrm{N}\phantom{\rule{0.2em}{0ex}}2p$ $\mathrm{B}\phantom{\rule{0.2em}{0ex}}2p$ characters is observed...
A strong molecule–surface interaction between free-base-tetra(4-bromophenyl)-porphyrin and Cu(111) results in a distortion of both the molecule underlying copper surface vicinity molecule. This turn leads to formation an intermediate complex due bonding iminic nitrogens atoms.
We describe the growth of a highly ordered pentacene film on Au(110) surface, investigated in both real and reciprocal space using scanning tunneling microscopy low-energy electron diffraction techniques. At high coverage, unidirectional multilayer π-stacked molecular row is formed with long-range order. Investigations interface at low coverage show that this arrangement direct consequence pentacene-induced surface reconstruction. Pentacene molecules initially adsorb between atomic gold rows...
Doubly excited neutral states of argon have been investigated by observing their decay into the 3p and 3s main ionisation lines satellite ionic states. These were measured using photoelectron spectroscopy monochromatic synchrotron radiation in range 31.0 to 42.3 eV. The line constant state spectra show structure due doubly but general these are much less prominent than for satellites which dominated resonances, particularly close threshold. There is also a strong selectivity with marked...
Investigations of chemical bonding and electronic structure features for polycrystalline (porphyrinato)nickel (II) (NiP, the simplest Ni porphyrin), (5,10,15,20-tetraphenylporphyrinato)nickel (NiTPP) (2-aza-21-carba-5,10,15,20-tetraphenylporphyrinato)nickel (N-confused NiTPP, NiNCTPP) have been performed by means high-resolution soft x-ray absorption photoemission spectroscopy. The 2p(3/2) spectra show strong π-back-bonding in these compounds leading to a high-energy shift (1.2 eV NiP NiTPP)...
A Ni–Cu ion exchange has been observed for (5,15-dibromo-10,20-diphenylporphyrinato)nickel(II) (NiDBrDPP) and (5,10,15,20-tetrakis(4-bromophenyl)porphyrinato)nickel(II) (NiTBrPP) on Cu(111). The proceeds at a faster rate the NiDBrDPP/Cu(111) system compared to NiTBrPP/Cu(111). This is explained in terms of macrocycle–substrate distance distortions that occur when molecules are deposited Cu(111) surface.
Adsorption of organic molecules on well-oriented single crystal coinage metal surfaces fundamentally affects the energy distribution curve ultra-violet photoelectron spectroscopy spectra. New features not present in spectrum pristine can be assigned as "interface states" having some degree molecule-substrate hybridization. Here it is shown that interface states molecular orbital character easily identified at low binding isolated above featureless substrate sp-plateau. On other hand much...
A study has been made of photodissociation processes in O2 which produce autoionizing fragments. Tunable VUV radiation was used to obtain photoelectron spectra. These contain structure due electron emission from states atomic oxygen decaying the ground and first excitated ion. The investigation concentrated on region thresholds for production autoionization, spectra have also recorded up 60 eV photon energy.
Doubly excited neutral states of neon, 2s22p4nln'l', have been investigated using photoelectron spectroscopy with synchrotron radiation. The selective decay these levels into all the energetically accessible ionic in range 50-60 eV has measured. In addition, Ne+ states, binding energies above first double ionisation potential, by autoionisation to Ne2+(3P) state observed.
We observe and characterise contamination-related differences in the packing density of wet-chemically deposited perylene bisimide derivatives on CVD graphene.
Autoionising states of atomic oxygen have been observed in the neutral photodissociation molecular by synchrotron radiation range 19-22 eV. The ejected electrons are measured high resolution electron spectroscopy and a two-dimensional scanning technique is used to distinguish between produced autoionisation photoelectrons exciting vibrational molecule. series identified which all decay O+ 4S ground state.