1
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Murray CP, Mamyraimov D, Ali M, Downing C, Povey IM, McCloskey D, O’Regan DD, Donegan JF. Monolayer Capping Provides Close to Optimal Resistance to Laser Dewetting of Au Films. ACS Appl Electron Mater 2023; 5:4080-4093. [PMID: 37637971 PMCID: PMC10448724 DOI: 10.1021/acsaelm.3c00052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/13/2023] [Indexed: 08/29/2023]
Abstract
Next-generation heat-assisted magnetic recording (HAMR) relies on fast, localized heating of the magnetic medium during the write process. Au plasmonic near-field transducers are an attractive solution to this challenge, but increased thermal stability of Au films is required to improve long-term reliability. This work compares the effect of nanoscale Al, AlOx, and Ta capping films on Au thin films with Ti or Ta adhesion layers for use in HAMR and other high-temperature plasmonic applications. Thermal stability is investigated using a bespoke laser dewetting system, and SEM and AFM are extensively used to interrogate the resulting dewet areas. The most effective capping layers are found to be 0.5-1 nm of Al or AlOx, which can eliminate dewetting under certain conditions. Even one monolayer of AlOx is shown to be highly effective in reducing dewetting. In the case of thicker capping layers of Ta and AlOx, the Au film can easily dewet underneath, leaving an intact capping layer. It is concluded that thinner capping layers are most effective against dewetting as the Au cannot dewet without breaking them and pulling them apart during the dewetting process. A simple model based on energetics considerations is developed, which explains how thinner capping layers can more effectively protect the metal from pore or fissure creation. The model provides some convenient guidelines for choosing both the substrate and capping layer, for a given metal, to maximize the resistance to laser-induced damage.
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Affiliation(s)
- Christopher P. Murray
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - Daniyar Mamyraimov
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - Mugahid Ali
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - Clive Downing
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - Ian M. Povey
- Tyndall
National Institute, Lee Maltings,
Prospect Row, Cork T12 R5CP, Ireland
| | - David McCloskey
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - David D. O’Regan
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
| | - John F. Donegan
- School
of Physics, CRANN and AMBER, Trinity College
Dublin, The University of Dublin, Dublin 2, Ireland
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2
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Bhandary S, Poli E, Teobaldi G, O’Regan DD. Dynamical Screening of Local Spin Moments at Metal-Molecule Interfaces. ACS Nano 2023; 17:5974-5983. [PMID: 36881865 PMCID: PMC10062023 DOI: 10.1021/acsnano.3c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Transition-metal phthalocyanine molecules have attracted considerable interest in the context of spintronics device development due to their amenability to diverse bonding regimes and their intrinsic magnetism. The latter is highly influenced by the quantum fluctuations that arise at the inevitable metal-molecule interface in a device architecture. In this study, we have systematically investigated the dynamical screening effects in phthalocyanine molecules hosting a series of transition-metal ions (Ti, V, Cr, Mn, Fe, Co, and Ni) in contact with the Cu(111) surface. Using comprehensive density functional theory plus Anderson's Impurity Model calculations, we show that the orbital-dependent hybridization and electron correlation together result in strong charge and spin fluctuations. While the instantaneous spin moments of the transition-metal ions are near atomic-like, we find that screening gives rise to considerable lowering or even quenching of these. Our results highlight the importance of quantum fluctuations in metal-contacted molecular devices, which may influence the results obtained from theoretical or experimental probes, depending on their possibly material-dependent characteristic sampling time-scales.
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Affiliation(s)
- Sumanta Bhandary
- School
of Physics and CRANN Institute, Trinity
College Dublin, The University
of Dublin, Dublin 2, Ireland
| | - Emiliano Poli
- Scientific
Computing Department, STFC UKRI, Rutherford
Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Gilberto Teobaldi
- Scientific
Computing Department, STFC UKRI, Rutherford
Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- School
of Chemistry, University of Southampton, Highfield SO17 1BJ, Southampton, United Kingdom
| | - David D. O’Regan
- School
of Physics and CRANN Institute, Trinity
College Dublin, The University
of Dublin, Dublin 2, Ireland
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3
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Almohammed S, K. Orhan O, Daly S, O’Regan DD, Rodriguez BJ, Casey E, Rice JH. Electric Field Tunability of Photoluminescence from a Hybrid Peptide-Plasmonic Metal Microfabricated Chip. JACS Au 2021; 1:1987-1995. [PMID: 35574042 PMCID: PMC8611722 DOI: 10.1021/jacsau.1c00323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Indexed: 06/14/2023]
Abstract
Enhancement of fluorescence through the application of plasmonic metal nanostructures has gained substantial research attention due to the widespread use of fluorescence-based measurements and devices. Using a microfabricated plasmonic silver nanoparticle-organic semiconductor platform, we show experimentally the enhancement of fluorescence intensity achieved through electro-optical synergy. Fluorophores located sufficiently near silver nanoparticles are combined with diphenylalanine nanotubes (FFNTs) and subjected to a DC electric field. It is proposed that the enhancement of the fluorescence signal arises from the application of the electric field along the length of the FFNTs, which stimulates the pairing of low-energy electrons in the FFNTs with the silver nanoparticles, enabling charge transport across the metal-semiconductor template that enhances the electromagnetic field of the plasmonic nanoparticles. Many-body perturbation theory calculations indicate that, furthermore, the charging of silver may enhance its plasmonic performance intrinsically at particular wavelengths, through band-structure effects. These studies demonstrate for the first time that field-activated plasmonic hybrid platforms can improve fluorescence-based detection beyond using plasmonic nanoparticles alone. In order to widen the use of this hybrid platform, we have applied it to enhance fluorescence from bovine serum albumin and Pseudomonas fluorescens. Significant enhancement in fluorescence intensity was observed from both. The results obtained can provide a reference to be used in the development of biochemical sensors based on surface-enhanced fluorescence.
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Affiliation(s)
- Sawsan Almohammed
- School
of Physics, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
- Conway
Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
| | - Okan K. Orhan
- School
of Physics, AMBER, and CRANN Institute, Trinity College Dublin, The University of Dublin, Dublin D02 PN40, Ireland
| | - Sorcha Daly
- School
of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
| | - David D. O’Regan
- School
of Physics, AMBER, and CRANN Institute, Trinity College Dublin, The University of Dublin, Dublin D02 PN40, Ireland
| | - Brian J. Rodriguez
- School
of Physics, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
- Conway
Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
| | - Eoin Casey
- School
of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
| | - James H. Rice
- School
of Physics, University College Dublin, Belfield, Dublin D04 V1W8, Ireland
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4
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Elibol K, Mangler C, O’Regan DD, Mustonen K, Eder D, Meyer JC, Kotakoski J, Hobbs RG, Susi T, Bayer BC. Single Indium Atoms and Few-Atom Indium Clusters Anchored onto Graphene via Silicon Heteroatoms. ACS Nano 2021; 15:14373-14383. [PMID: 34410707 PMCID: PMC8482752 DOI: 10.1021/acsnano.1c03535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Single atoms and few-atom nanoclusters are of high interest in catalysis and plasmonics, but pathways for their fabrication and placement remain scarce. We report here the self-assembly of room-temperature-stable single indium (In) atoms and few-atom In clusters (2-6 atoms) that are anchored to substitutional silicon (Si) impurity atoms in suspended monolayer graphene membranes. Using atomically resolved scanning transmission electron microscopy (STEM), we find that the symmetry of the In structures is critically determined by the three- or fourfold coordination of the Si "anchors". All structures are produced without electron-beam induced materials modification. In turn, when activated by electron beam irradiation in the STEM, we observe in situ the formation, restructuring, and translation of the Si-anchored In structures. Our results on In-Si-graphene provide a materials system for controlled self-assembly and heteroatomic anchoring of single atoms and few-atom nanoclusters on graphene.
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Affiliation(s)
- Kenan Elibol
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
the SFI Advanced Materials and Bio-Engineering Research Centre (AMBER), Dublin 2, Ireland
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, Dublin 2, Ireland
| | - Clemens Mangler
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - David D. O’Regan
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
the SFI Advanced Materials and Bio-Engineering Research Centre (AMBER), Dublin 2, Ireland
- School
of Physics, Trinity College Dublin, The
University of Dublin, Dublin 2, Ireland
| | - Kimmo Mustonen
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - Dominik Eder
- Institute
of Materials Chemistry, Vienna University
of Technology (TU Wien), Getreidemarkt 9/165, A-1060 Vienna, Austria
| | - Jannik C. Meyer
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
- Institute
for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Jani Kotakoski
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - Richard G. Hobbs
- Centre
for Research on Adaptive Nanostructures and Nanodevices (CRANN) and
the SFI Advanced Materials and Bio-Engineering Research Centre (AMBER), Dublin 2, Ireland
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, Dublin 2, Ireland
| | - Toma Susi
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - Bernhard C. Bayer
- University
of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090, Vienna, Austria
- Institute
of Materials Chemistry, Vienna University
of Technology (TU Wien), Getreidemarkt 9/165, A-1060 Vienna, Austria
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5
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Zhussupbekov K, Walshe K, Walls B, Ionov A, Bozhko SI, Ksenz A, Mozhchil RN, Zhussupbekova A, Fleischer K, Berman S, Zhilyaev I, O’Regan DD, Shvets IV. Surface Modification and Subsequent Fermi Density Enhancement of Bi(111). J Phys Chem C Nanomater Interfaces 2021; 125:5549-5558. [PMID: 34276852 PMCID: PMC8279637 DOI: 10.1021/acs.jpcc.0c07345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 02/24/2021] [Indexed: 06/13/2023]
Abstract
Defects introduced to the surface of Bi(111) break the translational symmetry and modify the surface states locally. We present a theoretical and experimental study of the 2D defects on the surface of Bi(111) and the states that they induce. Bi crystals cleaved in ultrahigh vacuum (UHV) at low temperature (110 K) and the resulting ion-etched surface are investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and scanning tunneling microscopy (STM) as well as spectroscopy (STS) techniques in combination with density functional theory (DFT) calculations. STS measurements of cleaved Bi(111) reveal that a commonly observed bilayer step edge has a lower density of states (DOS) around the Fermi level as compared to the atomic-flat terrace. Following ion bombardment, the Bi(111) surface reveals anomalous behavior at both 110 and 300 K: Surface periodicity is observed by LEED, and a significant increase in the number of bilayer step edges and energetically unfavorable monolayer steps is observed by STM. It is suggested that the newly exposed monolayer steps and the type A bilayer step edges result in an increase to the surface Fermi density as evidenced by UPS measurements and the Kohn-Sham DOS. These states appear to be thermodynamically stable under UHV conditions.
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Affiliation(s)
- Kuanysh Zhussupbekov
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Killian Walshe
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Brian Walls
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Andrei Ionov
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Sergei I. Bozhko
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Andrei Ksenz
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Rais N. Mozhchil
- Institute
of Solid State Physics, Russian Academy
of Sciences, Chernogolovka, Russia
| | - Ainur Zhussupbekova
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Karsten Fleischer
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- School
of Physical Sciences, Dublin City University, Dublin 9, Ireland
| | - Samuel Berman
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - Ivan Zhilyaev
- Institute
of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka, Russia
| | - David D. O’Regan
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- AMBER,
the SFI Research Centre for Advanced Materials and BioEngineering
Research, Dublin 2, Ireland
| | - Igor V. Shvets
- School
of Physics and Centre for Research on Adaptive Nanostructures and
Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
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