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Perera PGT, Linklater DP, Vilagosh Z, Nguyen THP, Hanssen E, Rubanov S, Wanjara S, Aadum B, Alfred R, Dekiwadia C, Juodkazis S, Croft R, Ivanova EP. Genetic Transformation of Plasmid DNA into Escherichia coli Using High Frequency Electromagnetic Energy. Nano Lett 2024; 24:1145-1152. [PMID: 38194429 DOI: 10.1021/acs.nanolett.3c03464] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
We present a novel technique of genetic transformation of bacterial cells mediated by high frequency electromagnetic energy (HF EME). Plasmid DNA, pGLO (5.4 kb), was successfully transformed into Escherichia coli JM109 cells after exposure to 18 GHz irradiation at a power density between 5.6 and 30 kW m-2 for 180 s at temperatures ranging from 30 to 40 °C. Transformed bacteria were identified by the expression of green fluorescent protein (GFP) using confocal scanning microscopy (CLSM) and flow cytometry (FC). Approximately 90.7% of HF EME treated viable E. coli cells exhibited uptake of the pGLO plasmid. The interaction of plasmid DNA with bacteria leading to transformation was confirmed by using cryogenic transmission electron microscopy (cryo-TEM). HF EME-induced plasmid DNA transformation was shown to be unique, highly efficient, and cost-effective. HF EME-induced genetic transformation is performed under physiologically friendly conditions in contrast to existing techniques that generate higher temperatures, leading to altered cellular integrity. This technique allows safe delivery of genetic material into bacterial cells, thus providing excellent prospects for applications in microbiome therapeutics and synthetic biology.
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Affiliation(s)
- Palalle G Tharushi Perera
- STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Denver P Linklater
- STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
- Biomedical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Zoltan Vilagosh
- STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - The Hong Phong Nguyen
- STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Eric Hanssen
- Ian Holmes Imaging Centre, Bio21 institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sergey Rubanov
- Ian Holmes Imaging Centre, Bio21 institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Steve Wanjara
- WaveCyte Biotechnologies, 9900 13th Ave N, Plymouth, Minnesota 55441, United States
| | - Bari Aadum
- WaveCyte Biotechnologies, 9900 13th Ave N, Plymouth, Minnesota 55441, United States
| | - Rebecca Alfred
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Chaitali Dekiwadia
- RMIT Microscopy and Microanalysis Facility, College of Science, Engineering and Health, RMIT University, P.O. Box 2476, Melbourne, VIC 3001, Australia
| | - Saulius Juodkazis
- Centre for Quantum and Optical Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Rodney Croft
- School of Psychology, Illawara Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Elena P Ivanova
- STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
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2
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Linklater DP, Le Guével X, Kosyer E, Rubanov S, Bryant G, Hanssen E, Baulin VA, Pereiro E, Perera PG, Wandiyanto JV, Angulo A, Juodkazis S, Ivanova EP. Functionalized Gold Nanoclusters Promote Stress Response in COS‐7 Cells. Advanced NanoBiomed Research 2023. [DOI: 10.1002/anbr.202200102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
| | - Xavier Le Guével
- Cancer Targets and Experimental Therapeutics Institute for Advanced Biosciences University of Grenoble Alpes 38700 La Tronche France
| | - Erim Kosyer
- STEM College School of Science RMIT University Melbourne VIC 3000 Australia
| | - Sergey Rubanov
- Ian Holmes Imaging Centre Bio21 University of Melbourne Parkville 3052 VIC Australia
| | - Gary Bryant
- STEM College School of Science RMIT University Melbourne VIC 3000 Australia
| | - Eric Hanssen
- Ian Holmes Imaging Centre Bio21 University of Melbourne Parkville 3052 VIC Australia
| | - Vladimir A. Baulin
- Departament de Química Física i Inorgànica Universitat Rovira i Virgili C/Marcel.lí Domingo s/n 43007 Tarragona Spain
| | - Eva Pereiro
- MISTRAL Beamline-Experiments Division ALBA Synchrotron Light Source Cerdanyola del Vallès 08290 Barcelona Spain
| | | | - Jason V. Wandiyanto
- Optical Sciences Centre Swinburne University of Technology Hawthorn VIC 3122 Australia
| | - Ana Angulo
- Immunology Unit Department of Biomedical Sciences Faculty of Medicine and Health Sciences University of Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer Barcelona Spain
| | - Saulius Juodkazis
- Optical Sciences Centre Swinburne University of Technology Hawthorn VIC 3122 Australia
| | - Elena P. Ivanova
- STEM College School of Science RMIT University Melbourne VIC 3000 Australia
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Johnson BC, Stuiber M, Creedon DL, Bose M, Berhane A, Willems van Beveren LH, Rubanov S, Cole JH, Mourik V, Hamilton AR, Duty TL, McCallum JC. Silicon-Aluminum Phase-Transformation-Induced Superconducting Rings. Nano Lett 2023; 23:17-24. [PMID: 36573935 DOI: 10.1021/acs.nanolett.2c02814] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The development of devices that exhibit both superconducting and semiconducting properties is an important endeavor for emerging quantum technologies. We investigate superconducting nanowires fabricated on a silicon-on-insulator (SOI) platform. Aluminum from deposited contact electrodes is found to interdiffuse with Si along the entire length of the nanowire, over micrometer length scales and at temperatures well below the Al-Si eutectic. The phase-transformed material is conformal with the predefined device patterns. The superconducting properties of a transformed mesoscopic ring formed on a SOI platform are investigated. Low-temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.
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Affiliation(s)
- Brett C Johnson
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Michael Stuiber
- Melbourne Centre for Nanofabrication, Clayton, Victoria3168, Australia
| | - Daniel L Creedon
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Manjith Bose
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Amanuel Berhane
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | | | - Sergey Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne, Parkville, Victoria3010, Australia
| | - Jared H Cole
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Vincent Mourik
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Alexander R Hamilton
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Timothy L Duty
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
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Zheng F, Raeber T, Rubanov S, Lee C, Seeber A, Hall C, Smith TA, Gao M, Angmo D, Ghiggino KP. Spontaneous Formation of a Ligand-Based 2D Capping Layer on the Surface of Quasi-2D Perovskite Films. ACS Appl Mater Interfaces 2022; 14:51910-51920. [PMID: 36374030 DOI: 10.1021/acsami.2c14929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-dimensional (2D) Ruddlesden-Popper phase perovskites (RPPs) are attracting growing attention for photovoltaic applications due to their enhanced stability compared to three-dimensional (3D) perovskites. The superior tolerance of 2D RPPs films to moisture and oxygen is mainly attributed to the hydrophobic nature of the introduced long-chain spacer cations (ligands). In this work, it is revealed that a thin capping layer, consisting of self-assembled butylammonium ligands, is spontaneously formed on the top surface of a quasi-2D perovskite film prepared by conventional one-step hot casting. Based on morphological and crystallographic analyses of both the top/bottom surfaces and the interior of quasi-2D perovskite films, the formation process of the 2D capping layer and the assembly of RPPs, comprising both large and small slab thickness (large-n, small-n), is elucidated. The vertical orientation of RPPs that is required for sufficient charge transport for 2D perovskite solar cells (PSCs) is further verified. We propose that the surface capping layer is directly responsible for the long-term stability of 2D PSCs. This work provides detailed insight into the microstructure of quasi-2D RPPs films that should assist the development of strategies for unlocking the full potential of 2D perovskites for high-performance PSCs and other solid-state electronic devices.
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Affiliation(s)
- Fei Zheng
- School of Chemistry and ARC Centre of Excellence in Exciton Science, The University of Melbourne, Parkville, Victoria3010, Australia
- Devices and Engineered Systems, CSIRO Manufacturing, Clayton, Victoria3168, Australia
| | - Thomas Raeber
- Materials Characterization and Modelling, CSIRO Manufacturing, Clayton, Victoria3168, Australia
| | - Sergey Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, The University of Melbourne, Parkville, Victoria3010, Australia
| | - Calvin Lee
- Bio21 Institute and School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Aaron Seeber
- Materials Characterization and Modelling, CSIRO Manufacturing, Clayton, Victoria3168, Australia
| | - Christopher Hall
- School of Chemistry and ARC Centre of Excellence in Exciton Science, The University of Melbourne, Parkville, Victoria3010, Australia
| | - Trevor A Smith
- School of Chemistry and ARC Centre of Excellence in Exciton Science, The University of Melbourne, Parkville, Victoria3010, Australia
| | - Mei Gao
- Devices and Engineered Systems, CSIRO Manufacturing, Clayton, Victoria3168, Australia
| | - Dechan Angmo
- Devices and Engineered Systems, CSIRO Manufacturing, Clayton, Victoria3168, Australia
| | - Kenneth P Ghiggino
- School of Chemistry and ARC Centre of Excellence in Exciton Science, The University of Melbourne, Parkville, Victoria3010, Australia
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Picollo F, Battiato A, Bosia F, Scaffidi Muta F, Olivero P, Rigato V, Rubanov S. Creation of pure non-crystalline diamond nanostructures via room-temperature ion irradiation and subsequent thermal annealing. Nanoscale Adv 2021; 3:4156-4165. [PMID: 36132848 PMCID: PMC9419479 DOI: 10.1039/d1na00136a] [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: 02/19/2021] [Accepted: 06/08/2021] [Indexed: 06/16/2023]
Abstract
Carbon exhibits a remarkable range of structural forms, due to the availability of sp3, sp2 and sp1 chemical bonds. Contrarily to other group IV elements such as silicon and germanium, the formation of an amorphous phase based exclusively on sp3 bonds is extremely challenging due to the strongly favored formation of graphitic-like structures at room temperature and pressure. As such, the formation of a fully sp3-bonded carbon phase requires an extremely careful (and largely unexplored) definition of the pressure and temperature across the phase diagram. Here, we report on the possibility of creating full-sp3 amorphous nanostructures within the bulk crystal of diamond with room-temperature ion-beam irradiation, followed by an annealing process that does not involve the application of any external mechanical pressure. As confirmed by numerical simulations, the (previously unreported) radiation-damage-induced formation of an amorphous sp2-free phase in diamond is determined by the buildup of extremely high internal stresses from the surrounding lattice, which (in the case of nanometer-scale regions) fully prevent the graphitization process. Besides the relevance of understanding the formation of exotic carbon phases, the use of focused/collimated ion beams discloses appealing perspectives for the direct fabrication of such nanostructures in complex three-dimensional geometries.
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Affiliation(s)
- F Picollo
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - A Battiato
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - F Bosia
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- Applied Science and Technology Department, Politecnico di Torino Torino 10129 Italy
| | - F Scaffidi Muta
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
| | - P Olivero
- Physics Department and "NIS Inter-departmental Centre", University of Torino Torino 10125 Italy
- National Institute of Nuclear Physics, Section of Torino Torino 10125 Italy
| | - V Rigato
- National Institute of Nuclear Physics, National Laboratories of Legnaro Legnaro 35020 Italy
| | - S Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne Victoria 3010 Australia
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Losurdo M, Gutiérrez Y, Suvorova A, Giangregorio MM, Rubanov S, Brown AS, Moreno F. Gallium Plasmonic Nanoantennas Unveiling Multiple Kinetics of Hydrogen Sensing, Storage, and Spillover. Adv Mater 2021; 33:e2100500. [PMID: 34076312 DOI: 10.1002/adma.202100500] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/03/2021] [Indexed: 06/12/2023]
Abstract
Hydrogen is the key element to accomplish a carbon-free based economy. Here, the first evidence of plasmonic gallium (Ga) nanoantennas is provided as nanoreactors supported on sapphire (α-Al2 O3 ) acting as direct plasmon-enhanced photocatalyst for hydrogen sensing, storage, and spillover. The role of plasmon-catalyzed electron transfer between hydrogen and plasmonic Ga nanoparticle in the activation of those processes is highlighted, as opposed to conventional refractive index-change-based sensing. This study reveals that, while temperature selectively operates those various processes, longitudinal (LO-LSPR) and transverse (TO-LSPR) localized surface plasmon resonances of supported Ga nanoparticles open selectivity of localized reaction pathways at specific sites corresponding to the electromagnetic hot-spots. Specifically, the TO-LSPR couples light into the surface dissociative adsorption of hydrogen and formation of hydrides, whereas the LO-LSPR activates heterogeneous reactions at the interface with the support, that is, hydrogen spillover into α-Al2 O3 and reverse-oxygen spillover from α-Al2 O3. This Ga-based plasmon-catalytic platform expands the application of supported plasmon-catalysis to hydrogen technologies, including reversible fast hydrogen sensing in a timescale of a few seconds with a limit of detection as low as 5 ppm and in a broad temperature range from room-temperature up to 600 °C while remaining stable and reusable over an extended period of time.
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Affiliation(s)
- Maria Losurdo
- Institute of Nanotechnology, CNR-NANOTEC, via Orabona 4, Bari, 70126, Italy
| | - Yael Gutiérrez
- Institute of Nanotechnology, CNR-NANOTEC, via Orabona 4, Bari, 70126, Italy
| | - Alexandra Suvorova
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | | | - Sergey Rubanov
- Bio21 Institute, University of Melbourne, 161 Barry Street, Parkville, Victoria, 3010, Australia
| | - April S Brown
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA
| | - Fernando Moreno
- Group of Optics, Department of Applied Physics, Faculty of Sciences, University of Cantabria, Avda. Los Castros s/n, Santander, 39005, Spain
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Fang F, Rogers J, Leveneur J, Rubanov S, Koo A, Kennedy J. Catalyst-free synthesis of copper oxide composites as solar radiative filters. Nanotechnology 2020; 31:504002. [PMID: 33006322 DOI: 10.1088/1361-6528/abb48e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Copper oxide composites were successfully synthesized by a catalyst-free method, plasma arc technology. The as-synthesized composites were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. The analysis revealed a mixture of crystalline copper oxide (CuO), cuprous oxide (Cu2O) and copper (Cu) phases of the copper oxide composites constitute of irregularly spheroidal particlesµ with nanoparticles aggregate on the surface. Gas pressure during plasma arc process noticeably influences the composition and solar radiative properties of the composite materials. Among the samples studied, the composites synthesized with an arc current of 80 A and a pressure of 300 Torr exhibited the highest near infrared diffuse reflectance, providing a total solar reflectance of 22.96%. The mixed phase composition together with the nanostructures among the composites are considered to contribute to the excellent near infrared reflectance of copper oxide composites. Low reflectance in the visible region combined with high reflectance in the near infrared region make this composite material a good candidate for solar reflective coating which will demonstrate black appearance but keep a cool surface under solar irradiation.
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Affiliation(s)
- Fang Fang
- National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand
| | - Joanne Rogers
- National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand
| | - Jérôme Leveneur
- National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand
- The Macdiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Sergey Rubanov
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Annette Koo
- Measurement Standards Laboratory, Gracefield Road, Lower Hutt, New Zealand
| | - John Kennedy
- National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand
- The Macdiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
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Jones A, Lam SKH, Du J, Rubanov S, Pan AV. Guided Vortex Motion Control in Superconducting Thin Films by Sawtooth Ion Surface Modification. ACS Appl Mater Interfaces 2020; 12:26170-26176. [PMID: 32408736 DOI: 10.1021/acsami.0c04658] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Design of flux profile and guided motion of magnetic flux quanta (also known as vortices) are central issues for functionality of superconducting devices. Anchoring vortex movement by trapping flux lines through the use of defects and preventing vortex entry by shielding magnetic field have been broadly explored, which can also enable reduction of noise for optimal device operation. Removing vortices entirely via the so-called ratchet effect (employing an asymmetric energy potential) is another alternative. This ratcheting potential is also used in DNA splitting, particle separation, surface atom electromigration, and electrophoresis. Utilizing a superconductor with the ratchet vortex pinning potential induces a dominant motion direction, which can be used to pump flux out from device functional zones. In this work, a varying thickness superconductor with its tailored intrinsic pinning mechanism has been simulated and proven to provide this preferential vortex motion. We demonstrate both theoretically and experimentally that a varying thickness superconducting ratchet is indeed possible. Furthermore, the sawtooth shape of the bridge provides a tunability to the preferred vortex motion direction, dependent on the ramp gradient and intrinsic pinning strength.
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Affiliation(s)
- Antony Jones
- Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, New South Wales 2522, Australia
- CSIRO Manufacturing, Bradfield Road, West Lindfield, New South Wales 2070, Australia
| | - Simon K H Lam
- CSIRO Manufacturing, Bradfield Road, West Lindfield, New South Wales 2070, Australia
| | - Jia Du
- CSIRO Manufacturing, Bradfield Road, West Lindfield, New South Wales 2070, Australia
| | - Sergey Rubanov
- Electron Microscope Unit, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Alexey V Pan
- Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, New South Wales 2522, Australia
- National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 31 Kashirskoye Shosse, Moscow 115409, Russian Federation
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9
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Linklater DP, De Volder M, Baulin VA, Werner M, Jessl S, Golozar M, Maggini L, Rubanov S, Hanssen E, Juodkazis S, Ivanova EP. High Aspect Ratio Nanostructures Kill Bacteria via Storage and Release of Mechanical Energy. ACS Nano 2018; 12:6657-6667. [PMID: 29851466 DOI: 10.1021/acsnano.8b01665] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The threat of a global rise in the number of untreatable infections caused by antibiotic-resistant bacteria calls for the design and fabrication of a new generation of bactericidal materials. Here, we report a concept for the design of antibacterial surfaces, whereby cell death results from the ability of the nanofeatures to deflect when in contact with attaching cells. We show, using three-dimensional transmission electron microscopy, that the exceptionally high aspect ratio (100-3000) of vertically aligned carbon nanotubes (VACNTs) imparts extreme flexibility, which enhances the elastic energy storage in CNTs as they bend in contact with bacteria. Our experimental and theoretical analyses demonstrate that, for high aspect ratio structures, the bending energy stored in the CNTs is a substantial factor for the physical rupturing of both Gram-positive and Gram-negative bacteria. The highest bactericidal rates (99.3% for Pseudomonas aeruginosa and 84.9% for Staphylococcus aureus) were obtained by modifying the length of the VACNTs, allowing us to identify the optimal substratum properties to kill different types of bacteria efficiently. This work highlights that the bactericidal activity of high aspect ratio nanofeatures can outperform both natural bactericidal surfaces and other synthetic nanostructured multifunctional surfaces reported in previous studies. The present systems exhibit the highest bactericidal activity of a CNT-based substratum against a Gram-negative bacterium reported to date, suggesting the possibility of achieving close to 100% bacterial inactivation on VACNT-based substrata.
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Affiliation(s)
- Denver P Linklater
- Faculty of Life and Social Sciences , Swinburne University of Technology , Hawthorn , Victoria 3122 , Australia
- Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Science, Engineering and Technology , Swinburne University of Technology , Hawthorn , Victoria 3122 , Australia
| | - Michael De Volder
- Institute for Manufacturing, Department of Engineering , University of Cambridge , Cambridge CB3 0FS , United Kingdom
| | - Vladimir A Baulin
- Department d'Enginyeria Quimica , Universitat Rovira, Virgili , 26 Av. dels Paisos Catalans , 43007 Tarragona , Spain
| | - Marco Werner
- Department d'Enginyeria Quimica , Universitat Rovira, Virgili , 26 Av. dels Paisos Catalans , 43007 Tarragona , Spain
| | - Sarah Jessl
- Institute for Manufacturing, Department of Engineering , University of Cambridge , Cambridge CB3 0FS , United Kingdom
| | - Mehdi Golozar
- Institute for Manufacturing, Department of Engineering , University of Cambridge , Cambridge CB3 0FS , United Kingdom
| | - Laura Maggini
- Institute for Manufacturing, Department of Engineering , University of Cambridge , Cambridge CB3 0FS , United Kingdom
| | - Sergey Rubanov
- Advanced Microscopy Facility, Bio21 Institute , University of Melbourne , 30 Flemington Rd , Parkville , Victoria 3010 , Australia
| | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Institute , University of Melbourne , 30 Flemington Rd , Parkville , Victoria 3010 , Australia
| | - Saulius Juodkazis
- Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Science, Engineering and Technology , Swinburne University of Technology , Hawthorn , Victoria 3122 , Australia
| | - Elena P Ivanova
- Faculty of Life and Social Sciences , Swinburne University of Technology , Hawthorn , Victoria 3122 , Australia
- School of Science, College of Science, Engineering and Health , RMIT University , GPO Box 2476, Melbourne , Victoria 3001 , Australia
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10
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Linklater DP, Juodkazis S, Rubanov S, Ivanova EP. Comment on "Bactericidal Effects of Natural Nanotopography of Dragonfly Wing on Escherichia coli". ACS Appl Mater Interfaces 2017; 9:29387-29393. [PMID: 28799744 DOI: 10.1021/acsami.7b05707] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Denver P Linklater
- Faculty of Life and Social Sciences, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia
- Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, Victory 3122, Australia
| | - Saulius Juodkazis
- Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, Victory 3122, Australia
| | - Sergey Rubanov
- Advanced Microscopy Facility, Bio21 Institute, University of Melbourne , 30 Flemington Road, 3010 Parkville, Victoria, Australia
| | - Elena P Ivanova
- Faculty of Life and Social Sciences, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia
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Nili H, Ahmed T, Walia S, Ramanathan R, Kandjani AE, Rubanov S, Kim J, Kavehei O, Bansal V, Bhaskaran M, Sriram S. Microstructure and dynamics of vacancy-induced nanofilamentary switching network in donor doped SrTiO 3-x memristors. Nanotechnology 2016; 27:505210. [PMID: 27861164 DOI: 10.1088/0957-4484/27/50/505210] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Donor doping of perovskite oxides has emerged as an attractive technique to create high performance and low energy non-volatile analog memories. Here, we examine the origins of improved switching performance and stable multi-state resistive switching in Nb-doped oxygen-deficient amorphous SrTiO3 (Nb:a-STO x ) metal-insulator-metal (MIM) devices. We probe the impact of substitutional dopants (i.e., Nb) in modulating the electronic structure and subsequent switching performance. Temperature stability and bias/time dependence of the switching behavior are used to ascertain the role of substitutional dopants and highlight their utility to modulate volatile and non-volatile behavior in a-STO x devices for adaptive and neuromorphic applications. We utilized a combination of transmission electron microscopy, photoluminescence emission properties, interfacial compositional evaluation, and activation energy measurements to investigate the microstructure of the nanofilamentary network responsible for switching. These results provide important insights into understanding mechanisms that govern the performance of donor-doped perovskite oxide-based memristive devices.
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Affiliation(s)
- Hussein Nili
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, VIC 3001, Australia
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Losurdo M, Suvorova A, Rubanov S, Hingerl K, Brown AS. Thermally stable coexistence of liquid and solid phases in gallium nanoparticles. Nat Mater 2016; 15:995-1002. [PMID: 27454047 DOI: 10.1038/nmat4705] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 06/21/2016] [Indexed: 06/06/2023]
Abstract
Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases.
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Affiliation(s)
- Maria Losurdo
- Institute of Nanotechnology, CNR-NANOTEC, via Orabona 4, 70126 Bari, Italy
| | - Alexandra Suvorova
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Sergey Rubanov
- Bio21 Institute, University of Melbourne, 161 Barry Street, Parkville 3010, Victoria, Australia
| | - Kurt Hingerl
- Center for Surface- and Nanoanalytics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - April S Brown
- Army Research Office, Engineering Sciences Directorate, Durham, North Carolina 27708, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
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13
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Murmu PP, Kennedy J, Williams GVM, Prakash T, Leveneur J, Chong SV, Rubanov S. Synthesis and Compositional Analysis of Permalloy Powder Prepared by Arc-Discharge. J Nanosci Nanotechnol 2015; 15:9612-9616. [PMID: 26682386 DOI: 10.1166/jnn.2015.10731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the synthesis, compositional, structural and magnetic properties of permalloy powders prepared using an arc-discharge method under different atmospheres. Ion beam analysis results showed that powder prepared in air had a higher concentration of oxygen than those prepared under nitrogen or argon atmospheres. X-ray diffraction measurements showed that powders prepared in air contained magnetite (Fe3O4) and other phases, while powders prepared under nitrogen or argon predominately contained permalloy. The permalloy powders contained a broad range of particle sizes, and nanoparticles as small as 10 nm were evident from transmission electron microscopy data. The saturation magnetizations were significantly lower for the powders prepared in air than those prepared under nitrogen or argon. This can be attributed to oxidation, where the saturation magnetization is predominately from Fe3O4 for powders made in air. The coercive fields were also significantly larger for powders prepared in air, which is consistent with the powders containing different phases when compared with the permalloy powders. Our results show that permalloy powders can be made in nitrogen and argon, allowing for the production of low oxygen content permalloy powders for device applications. Our results also suggest that the use of an iron anode could result in Fe3O4 powders.
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14
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Losurdo M, Yi C, Suvorova A, Rubanov S, Kim TH, Giangregorio MM, Jiao W, Bergmair I, Bruno G, Brown AS. Demonstrating the capability of the high-performance plasmonic gallium-graphene couple. ACS Nano 2014; 8:3031-41. [PMID: 24575951 DOI: 10.1021/nn500472r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Metal nanoparticle (NP)-graphene multifunctional platforms are of great interest for exploring strong light-graphene interactions enhanced by plasmons and for improving performance of numerous applications, such as sensing and catalysis. These platforms can also be used to carry out fundamental studies on charge transfer, and the findings can lead to new strategies for doping graphene. There have been a large number of studies on noble metal Au-graphene and Ag-graphene platforms that have shown their potential for a number of applications. These studies have also highlighted some drawbacks that must be overcome to realize high performance. Here we demonstrate the promise of plasmonic gallium (Ga) nanoparticle (NP)-graphene hybrids as a means of modulating the graphene Fermi level, creating tunable localized surface plasmon resonances and, consequently, creating high-performance surface-enhanced Raman scattering (SERS) platforms. Four prominent peculiarities of Ga, differentiating it from the commonly used noble (gold and silver) metals are (1) the ability to create tunable (from the UV to the visible) plasmonic platforms, (2) its chemical stability leading to long-lifetime plasmonic platforms, (3) its ability to n-type dope graphene, and (4) its weak chemical interaction with graphene, which preserves the integrity of the graphene lattice. As a result of these factors, a Ga NP-enhanced graphene Raman intensity effect has been observed. To further elucidate the roles of the electromagnetic enhancement (or plasmonic) mechanism in relation to electron transfer, we compare graphene-on-Ga NP and Ga NP-on-graphene SERS platforms using the cationic dye rhodamine B, a drug model biomolecule, as the analyte.
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Affiliation(s)
- Maria Losurdo
- Electrical and Computer Engineering Department, Duke University , Durham, North Carolina 27705, United States
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15
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Bosia F, Argiolas N, Bazzan M, Fairchild BA, Greentree AD, Lau DWM, Olivero P, Picollo F, Rubanov S, Prawer S. Direct measurement and modelling of internal strains in ion-implanted diamond. J Phys Condens Matter 2013; 25:385403. [PMID: 23988841 DOI: 10.1088/0953-8984/25/38/385403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present a phenomenological model and finite element simulations to describe the depth variation of mass density and strain of ion-implanted single-crystal diamond. Several experiments are employed to validate the approach: firstly, samples implanted with 180 keV B ions at relatively low fluences are characterized using high-resolution x-ray diffraction; secondly, the mass density variation of a sample implanted with 500 keV He ions, well above its amorphization threshold, is characterized with electron energy loss spectroscopy. At high damage densities, the experimental depth profiles of strain and density display a saturation effect with increasing damage and a shift of the damage density peak towards greater depth values with respect to those predicted by TRIM simulations, which are well accounted for in the model presented here. The model is then further validated by comparing transmission electron microscopy-measured and simulated thickness values of a buried amorphous carbon layer formed at different depths by implantation of 500 keV He ions through a variable-thickness mask to simulate the simultaneous implantation of ions at different energies.
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Affiliation(s)
- F Bosia
- Department of Physics-NIS Centre of Excellence, Università di Torino, Italy.
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16
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Alves ADC, Newnham J, van Donkelaar JA, Rubanov S, McCallum JC, Jamieson DN. Controlled deterministic implantation by nanostencil lithography at the limit of ion-aperture straggling. Nanotechnology 2013; 24:145304. [PMID: 23508018 DOI: 10.1088/0957-4484/24/14/145304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Solid state electronic devices fabricated in silicon employ many ion implantation steps in their fabrication. In nanoscale devices deterministic implants of dopant atoms with high spatial precision will be needed to overcome problems with statistical variations in device characteristics and to open new functionalities based on controlled quantum states of single atoms. However, to deterministically place a dopant atom with the required precision is a significant technological challenge. Here we address this challenge with a strategy based on stepped nanostencil lithography for the construction of arrays of single implanted atoms. We address the limit on spatial precision imposed by ion straggling in the nanostencil-fabricated with the readily available focused ion beam milling technique followed by Pt deposition. Two nanostencils have been fabricated; a 60 nm wide aperture in a 3 μm thick Si cantilever and a 30 nm wide aperture in a 200 nm thick Si3N4 membrane. The 30 nm wide aperture demonstrates the fabricating process for sub-50 nm apertures while the 60 nm aperture was characterized with 500 keV He(+) ion forward scattering to measure the effect of ion straggling in the collimator and deduce a model for its internal structure using the GEANT4 ion transport code. This model is then applied to simulate collimation of a 14 keV P(+) ion beam in a 200 nm thick Si3N4 membrane nanostencil suitable for the implantation of donors in silicon. We simulate collimating apertures with widths in the range of 10-50 nm because we expect the onset of J-coupling in a device with 30 nm donor spacing. We find that straggling in the nanostencil produces mis-located implanted ions with a probability between 0.001 and 0.08 depending on the internal collimator profile and the alignment with the beam direction. This result is favourable for the rapid prototyping of a proof-of-principle device containing multiple deterministically implanted dopants.
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Affiliation(s)
- A D C Alves
- Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Victoria 3010, Australia.
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17
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Fedoseev SA, Pan AV, Rubanov S, Golovchanskiy IA, Shcherbakova OV. Large, controllable spikes of magnetoresistance in La(2/3)Ca(1/3)MnO3/SrTiO3 superlattices. ACS Nano 2013; 7:286-293. [PMID: 23241017 DOI: 10.1021/nn304127n] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have investigated superlattices consisting of up to 30 epitaxial nanomultilayers (3-7 nm thick) of ferromagnetic La(2/3)Ca(1/3)MnO(3) (LCMO) and insulating SrTiO(3) (STO) hybrids. The superlattices demonstrate dramatic shifts of Curie temperature, indicating the possibility of its tunability. The metal-insulator transition (MIT) has been observed around 140 K. Below the MIT temperature, the superlattices have shown sharp drops of resistivity, facilitating the largest and sharpest magnetoresistance peaks (>2000%) ever observed in LCMO films and superlattices at low temperatures. The observed experimental results can be explained in the frame of the phase separation model in manganites with well-organized structures. The results of magnetic and transport measurements of such hybrid structures are discussed, indicating a magnetodielectric effect in STO interlayers. The magnetic and transport properties of the superlattices are shown to be technology-dependent, experiencing dimensional transitions, which enables the creation of structures with prescribed magnetoresistance characteristics for a broad range of applications.
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Affiliation(s)
- Sergey A Fedoseev
- Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
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18
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MacDonald BI, Martucci A, Rubanov S, Watkins SE, Mulvaney P, Jasieniak JJ. Layer-by-layer assembly of sintered CdSe(x)Te1-x nanocrystal solar cells. ACS Nano 2012; 6:5995-6004. [PMID: 22690798 DOI: 10.1021/nn3009189] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Alloying is a versatile tool for engineering the optical and electronic properties of materials. Here, we explore the use of CdTe and CdSe nanocrystals in developing sintered CdSe(x)Te(1-x) alloys as bandgap tunable, light-absorbing layers for solution-processed solar cells. Using a layer-by-layer approach, we incorporate such alloyed materials into single- and graded-composition device architectures. Nanostructured solar cells employing CdSe(x)Te(1-x) layers are found to exhibit a spectral response deeper into the IR region than bulk CdTe devices as a result of optical bowing and achieve power conversion efficiencies as high as 7.1%. The versatility of the layer-by-layer approach is highlighted through the fabrication of compositionally graded solar cells in which the [Se]:[Te] ratio is varied across the device. Each of the individual layers can be clearly resolved through cross-sectional imaging and show limited interdiffusion. Such devices demonstrate the importance of band-alignment in the development of highly efficient, nanostructured solar cells.
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Affiliation(s)
- Brandon I MacDonald
- School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
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19
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Fairchild BA, Rubanov S, Lau DWM, Robinson M, Suarez-Martinez I, Marks N, Greentree AD, McCulloch D, Prawer S. Mechanism for the amorphisation of diamond. Adv Mater 2012; 24:2024-2029. [PMID: 22419269 DOI: 10.1002/adma.201104511] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/25/2012] [Indexed: 05/31/2023]
Abstract
The breakdown of the diamond lattice is explored by ion implantation and molecular dynamics simulations. We show that lattice breakdown is strain-driven, rather than damage-driven, and that the lattice persists until 16% of the atoms have been removed from their lattice sites. The figure shows the transition between amorphous carbon and diamond, with the interfaces highlighted with dashed lines.
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20
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Rollinson CM, Huntington ST, Gibson BC, Rubanov S, Canning J. Characterization of nanoscale features in tapered fractal and photonic crystal fibers. Opt Express 2011; 19:1860-1865. [PMID: 21369001 DOI: 10.1364/oe.19.001860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The internal structure of nanostructured air-silica fiber probes have been characterized using a combined focused ion beam and scanning electron microscopy technique. The collapse rate of the air-holes is shown to differ substantially between a regular photonic crystal fiber (PCF) and the quasi-periodic Fractal fiber. The integrity of the Fractal fiber structure is maintained down to an outer diameter as small as 120 nm, whereas the air-holes of the regular PCF begin to collapse when the outer diameter is approximately 820 nm. The observed smallest hole diameter of 10 nm is suggested to be due to physical limits imposed by the molecular structure of silica. These results confirm structural inferences made in previous publications.
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Affiliation(s)
- C M Rollinson
- School of Physics, The University of Melbourne, Parkville, Victoria, 3010, Australia
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21
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Tettamanzi GC, Pakes CI, Potenza A, Rubanov S, Marrows CH, Prawer S. Superconducting transition in Nb nanowires fabricated using focused ion beam. Nanotechnology 2009; 20:465302. [PMID: 19843991 DOI: 10.1088/0957-4484/20/46/465302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Making use of focused Ga-ion beam (FIB) fabrication technology, the evolution with device dimension of the low-temperature electrical properties of Nb nanowires has been examined in a regime where crossover from Josephson-like to insulating behaviour is evident. Resistance-temperature data for devices with a physical width of order 100 nm demonstrate suppression of superconductivity, leading to dissipative behaviour that is shown to be consistent with the activation of phase-slip below T(c). This study suggests that by exploiting the Ga-impurity poisoning introduced by the FIB into the periphery of the nanowire, a central superconducting phase-slip nanowire with sub-10 nm dimensions may be engineered within the core of the nanowire.
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Affiliation(s)
- G C Tettamanzi
- School of Physics, University of Melbourne, Victoria 3010, Australia.
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22
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Fang JH, Spizzirri P, Cimmino A, Rubanov S, Prawer S. Extremely high aspect ratio alumina transmission nanomasks: their fabrication and characterization using electron microscopy. Nanotechnology 2009; 20:065706. [PMID: 19417400 DOI: 10.1088/0957-4484/20/6/065706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Free standing, nanoporous alumina templates were fabricated as transmission masks from aluminium using a two-step anodization process followed by acid etching. The resulting membrane comprises self-ordered, periodic arrays of non-connecting circular channels which can be prepared with pore diameters <100 nm and with minimal occlusion. Aspect ratios greater than 300:1 were measured directly using electron transmission and the channels were shown to be highly aligned (angular) over membrane thicknesses of tens of microns. Also evident is some local order associated with both azimuthal and angular domain structure giving rise to local channel tilt which has not previously been reported. Transmission electron microscopy has been shown to be an important characterization tool for these nanomasks as the channels are transparent to electrons, providing a means of directly measuring their thickness and aspect ratio. Expressions for determining their thickness and aspect ratio are also presented and evaluated in this work. These membranes are well suited for use as nanotemplates in transmission lithography applications including ion implantation and ion or electron beam collimation.
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Affiliation(s)
- Jing-Hua Fang
- School of Physics, University of Melbourne, Victoria, 3010, Australia
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23
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Sedoglavich N, Sharpe JC, Künnemeyer R, Rubanov S. Polarisation and wavelength selective transmission through nanohole structures with multiple grating geometry. Opt Express 2008; 16:5832-7. [PMID: 18542694 DOI: 10.1364/oe.16.005832] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Excitation and localization of surface plasmon polariton modes in metal-dielectric structures can be utilized to construct nanophotonic materials and devices with tuneable optical dispersion. We present a selective polariton generator (SPG) device that demonstrates switching of light transmission based on surface plasmon antennae principles. This polarization-sensitive structure selectively generates and transports polaritons of a desired wavelength through subwavelength apertures. Two of these SPGs have been combined around a nanohole into a new, single device that allows polarization and wavelength selective switching of transmission. The multi-state operation is confirmed by experiment results.
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Affiliation(s)
- Nemanya Sedoglavich
- Department of Engineering, The University of Waikato, Private Bag 3015, Hamilton 3240, New Zealand.
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Santori C, Fattal D, Spillane SM, Fiorentino M, Beausoleil RG, Greentree AD, Olivero P, Draganski M, Rabeau JR, Reichart P, Gibson BC, Rubanov S, Jamieson DN, Prawer S. Coherent population trapping in diamond N-V centers at zero magnetic field. Opt Express 2006; 14:7986-7993. [PMID: 19529168 DOI: 10.1364/oe.14.007986] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Coherent population trapping at zero magnetic field was observed for nitrogen-vacancy centers in diamond under optical excitation. This was measured as a reduction in photoluminescence when the detuning between two excitation lasers matched the 2.88 GHz crystal-field splitting of the color center ground states. This behavior is highly sensitive to strain, which modifies the excited states, and was unexpected following recent experiments demonstrating optical readout of single nitrogen-vacancy electron spins based on cycling transitions. These results demonstrate for the first time that three-level Lambda configurations suitable for proposed quantum information applications can be realized simultaneously for all four orientations of nitrogen-vacancy centers at zero magnetic field.
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25
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Gibson B, Huntington S, Rubanov S, Olivero P, Digweed-Lyytikäinen K, Canning J, Love J. Exposure and characterization of nano-structured hole arrays in tapered photonic crystal fibers using a combined FIB/SEM technique. Opt Express 2005; 13:9023-9028. [PMID: 19498937 DOI: 10.1364/opex.13.009023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This paper presents a technique to expose and characterize nano-structured hole arrays in tapered photonic crystal fibers. Hole array structures are examined with taper outer diameters ranging from 12.9 microm to 1.6 microm. A combined focused ion beam milling and scanning electron microscope system was used to expose and characterize the arrayed air-silica structures. Results from this combined technique are presented which resolve hole-to-hole pitch sizes and hole diameters in the order of 120 nm and 60 nm, respectively.
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Abstract
The damage layers generated in III-V compounds exposed to energetic gallium ions in a focused ion beam (FIB) instrument have been characterized by transmission electron microscopy (TEM). The damage on the side walls of the milled trenches is in the form of amorphous layers associated with direct amorphization from the gallium beam, rather than from redeposition of milled material. However, the damage on the bottom of the milled trenches is more complex. For InP and InAs the damage layers include the presence of crystalline phases resulting from recrystallization associated heating from the incident beam and gallium implantation. In contrast, such crystalline phases are not present in GaAs. The thicknesses of the damage layers are greater than those calculated from theoretical models of ion implantation. These differences arise because the dynamic nature of FIB milling means that the energetic ion beams pass through already damaged layers. In InP recoil phosphorus atoms also cause significant damage.
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Affiliation(s)
- S Rubanov
- Electron Microscope Unit, University of NSW, Sydney 2052, Australia.
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Rubanov S, Munroe PR. The application of FIB milling for specimen preparation from crystalline germanium. Micron 2004; 35:549-56. [PMID: 15219901 DOI: 10.1016/j.micron.2004.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2002] [Revised: 12/15/2003] [Accepted: 03/16/2004] [Indexed: 11/20/2022]
Abstract
The effectiveness of focused ion beam (FIB) for preparation of crystalline germanium specimens has been studied. FIB milling results in strong cellular relief of the germanium surfaces on bulk specimens. This cellular relief, associated with the generation of high densities of point defects during interaction of the specimen with the high-energy gallium beam, can be reduced by using either a lower ion beam currents or a lower beam energy. Even under these milling conditions the cellular relief is, however, still evident on the surface of the TEM specimens as evidenced by so-called 'curtaining' relief. Nevertheless good quality specimens for both conventional and high-resolution imaging may be prepared using FIB milling if low currents are employed for final milling.
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Affiliation(s)
- S Rubanov
- Electron Microscope Unit, University of New South Wales, Kensington, NSW 2052 Sydney, Australia
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Abstract
The damage created in silicon transmission electron microscope specimens prepared using a focused ion beam miller is assessed using cross-sections of trenches milled under different beam conditions. Side-wall damage consists of an amorphous layer formed by direct interaction with the energetic gallium ion beam; a small amount of implanted gallium is also detected. By contrast, bottom-wall damage layers are more complex and contain both amorphous films and crystalline regions that are richer in implanted gallium. More complex milling sequences show that redeposition of milled material, enriched in gallium, can occur depending on the geometry of the mill employed. The thickness of the damage layers depends strongly on beam energy, but is independent of beam current. Monte Carlo modelling of the damage formed indicates that recoil silicon atoms contribute significantly to the damaged formed in the specimen.
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Affiliation(s)
- S Rubanov
- School of Physics, University of Melbourne, Victoria 3010, Australia
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