ORCID Profile
0000-0002-2746-1363
Current Organisations
Australian National University
,
University of Western Australia
,
University of Technology Sydney
,
Nature Publishing Group
,
FEI Co
,
University of Cambridge
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Nanomaterials | Nanotechnology | Catalysis and Mechanisms of Reactions | Functional Materials | Nanoscale Characterisation | Nanofabrication, Growth and Self Assembly |
ANZSRC Socio-Economic Objective (SEO)
Manufacturing Standards and Calibrations | Fuel Cells (excl. Solid Oxide) | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology | Management of Gaseous Waste from Transport Activities (excl. Greenhouse Gases)
Related Links
Publications
Atomically Thin Gallium Nitride for High‐Performance Photodetection
Publisher: Wiley
Date: 07-05-2023
Abstract: Gallium nitride (GaN) technology has matured and commercialised for optoelectronic devices in the ultraviolet (UV) spectrum over the last few decades. Simultaneously, atomically thin materials with unique features have emerged as contenders for device miniaturization. However, the lack of successful techniques to produce ultra‐thin GaN prevents access to these new predicted properties. Here, this important gap is addressed by printing millimeter‐large ultra‐thin GaN nanosheets (NS) (≈1.4 nm) using a simple two‐step process that simultaneously introduces nitrogen point defects. This extends the photoelectrical spectral response from UV (280 nm) to near infrared (NIR) (1080 nm). The GaN‐based photodetectors display excellent figures of merit, having a responsivity (2.72 × 10 4 A W −1 ) up to four orders of magnitude higher than the commercial photodetectors at room temperature, despite being 10 2 –10 3 times thinner. The photodetectors exhibit fast switching, with rise and decay time in the range of microseconds. The state‐of‐the‐art device performance originates from the ultra‐thin nature of GaN NS coupled with nitrogen point vacancies in the synthesis process. This work presents the opportunity to significantly expand the reach of GaN semiconductor technology and may lead to applications in high‐performance miniaturized imaging systems, spectroscopy, communication, and integrated optoelectronic circuits.
Electron beam directed etching of hexagonal boron nitride
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR04959A
Abstract: High resolution directed electron beam etching of hBN using water as the precursor gas.
Ultra-bright emission from hexagonal boron nitride defects as a new platform for bio-imaging and bio-labelling
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2242988
A photometric catalogue of galaxies in the cluster Abell 85
Publisher: EDP Sciences
Date: 02-1998
DOI: 10.1051/AAS:1998128
Stark Effect of Blue Quantum Emitters in Hexagonal Boron Nitride
Publisher: American Physical Society (APS)
Date: 05-04-2023
Optical Properties of Self-Organized InGaAs/GaAs Quantum Dots in Field-Effect Structures
Publisher: Springer Science and Business Media LLC
Date: 1998
DOI: 10.1557/PROC-536-269
Abstract: The results of photoluminescence (PL) and electroreflectance (ER) measurements on InGaAs/GaAs self-organized quantum dots (QDs) in field-effect structure are presented. It has been found that the QDs PL can be completely quenched in reversely biased structure both at room temperature and at T=4.2K. A non-monotonic dependence of QDs PL peak energy with applied bias is observed at low temperature, which is attributed to the band-gap re-normalization due to QDs charging and size distribution effects. The electric field dependence of the QDs ER feature at room temperature has been analysed. A red shift of that feature with increasing electric field has been observed.
Effects of proton irradiation on luminescence emission and carrier dynamics of self-assembled III-V quantum dots
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2002
Single-photon emission from exciton complexes in individual quantum dots
Publisher: American Physical Society (APS)
Date: 18-10-2001
A TEM and powder XRD study of new fluorite and perovskite-related phases in the CaO-ZrO2-Ta2O5 system
Publisher: Elsevier BV
Date: 11-1996
Horizontal movements, vertical-habitat utilization and diet of the jumbo squid (Dosidicus gigas) in the Pacific Ocean off Baja California Sur, Mexico
Publisher: Elsevier BV
Date: 07-2010
A modulation wave approach to the structural characterization of three new cristobalite-related sodium magnesiosilicates
Publisher: International Union of Crystallography (IUCr)
Date: 1918
DOI: 10.1107/S0108768196012335
Abstract: The crystal structures of three new cristobalite-related sodium magnesiosilicates [Na 2 MgSiO 4 , M r = 162.37, orthorhombic, Pna 2 1 , a = 10.835 (5), b = 5.279 (12), c = 7.067 (8) Å, D x = 2.668 g cm −3 , Z = 4, Cu K α, λ = 1.5418 Å, μ = 75.96 cm −l , F (000) = 319.87 Na 1.74 Mg 0.79 Al 0.15 Si 1.06 O 4 , M r = 157.02, orthorhombic, Pbca , a = 10.487 (7), b = 14.351 (4), c = 5.243 (6) Å, D x = 2.643 g cm −3 , Z = 8, Cu K α, λ = 1.5418 Å, μ = 76.70 cm −l , F (000) = 619.04 Na 1.8 Mg 0.9 Si 1.1 O 4 , M r = 158.15, tetragonal, P 4 1 2 1 2, a = 5.330 (6), c = 7.086 (5) Å, D x = 2.609 g cm −3 , Z = 2, Cu K α, λ= 1.5418 Å, μ = 75.44 cm −l , F (000) = 155.94] are determined by Rietveld refinement from X-ray powder diffraction data. Plausible starting models were derived from a modulation wave approach based on the ideal C9 structure type and assuming regular SiO 4 and MgO 4 tetrahedra.
Electrically modulated photoluminescence in self-organized InGaAs/GaAs quantum dots
Publisher: AIP Publishing
Date: 09-11-1998
DOI: 10.1063/1.122598
Abstract: Results of photoluminescence (PL) study of the self-organized InGaAs/GaAs quantum dots (QDs) in a field-effect structure grown by metalorganic vapor phase epitaxy are presented. It has been found that the PL from the QDs strongly depends on the bias voltage. No PL from the QDs ground state can be observed from the reverse biased structure, whereas the PL signal recovers in the forward biased structure. It is proposed that the bias dependence of the PL signal results from the QDs electron occupancy changes driven by the electric field within the structure. Due to a long thermalization time, the photogenerated electrons are swept out of the QDs by the electric field before radiative recombination. The electrically modulated PL (e-m PL), making use of the bias dependence of PL signal, is proposed as a tool for QD investigation. The e-m PL spectra at T=300 and T=4.2 K are analyzed and discussed.
Localized Probing of Gas Molecule Adsorption Energies and Desorption Attempt Frequencies
Publisher: American Chemical Society (ACS)
Date: 02-07-2015
Self-forming InAs/GaP quantum dots by direct island growth
Publisher: AIP Publishing
Date: 16-03-1998
DOI: 10.1063/1.121070
Abstract: InAs/GaP semiconductor quantum dots (QDs) were spontaneously formed using direct island growth (Volmer–Weber) rather than Stranski–Krastanow (S-K) growth. Structural investigations of InAs/GaP QDs suggest kinetically limited growth and show a broad size distribution. Photoluminescence and cathodoluminescence spectroscopy reveal large inhomogeneous broadening with the emission peak centering at 1.7 eV. Device applications exploiting broad optical emission in QDs are discussed.
In situstudy of the precursor conversion reactions during solventless synthesis of Co9S8, Ni3S2, Co and Ni nanowires
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR02093K
Abstract: Synthesis of Co 9 S 8 , Ni 3 S 2 , Co and Ni nanowires by solventless thermolysis of a mixture of metal( ii ) acetate and cysteine in vacuum is reported.
Versatile method for template-free synthesis of single crystalline metal and metal alloy nanowires
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5NR07307C
Abstract: A versatile, template-free growth technique for single crystalline metal nanowires using gas or solution phase precursors.
All-optical control and super-resolution imaging of quantum emitters in layered materials
Publisher: Springer Science and Business Media LLC
Date: 28-02-2018
DOI: 10.1038/S41467-018-03290-0
Abstract: Layered van der Waals materials are emerging as compelling two-dimensional platforms for nanophotonics, polaritonics, valleytronics and spintronics, and have the potential to transform applications in sensing, imaging and quantum information processing. Among these, hexagonal boron nitride (hBN) is known to host ultra-bright, room-temperature quantum emitters, whose nature is yet to be fully understood. Here we present a set of measurements that give unique insight into the photophysical properties and level structure of hBN quantum emitters. Specifically, we report the existence of a class of hBN quantum emitters with a fast-decaying intermediate and a long-lived metastable state accessible from the first excited electronic state. Furthermore, by means of a two-laser repumping scheme, we show an enhanced photoluminescence and emission intensity, which can be utilized to realize a new modality of far-field super-resolution imaging. Our findings expand current understanding of quantum emitters in hBN and show new potential ways of harnessing their nonlinear optical properties in sub-diffraction nanoscopy.
Deterministic Nanopatterning of Diamond Using Electron Beams
Publisher: American Chemical Society (ACS)
Date: 24-01-2018
Abstract: Diamond is an ideal material for a broad range of current and emerging applications in tribology, quantum photonics, high-power electronics, and sensing. However, top-down processing is very challenging due to its extreme chemical and physical properties. Gas-mediated electron beam-induced etching (EBIE) has recently emerged as a minimally invasive, facile means to dry etch and pattern diamond at the nanoscale using oxidizing precursor gases such as O
Localized deposition of pure platinum nanostructures
Publisher: IEEE
Date: 12-2014
Stable and Metastable InGaAs/GaAs Island Shapes and Surfactantlike Suppression of the Wetting Transformation
Publisher: American Physical Society (APS)
Date: 21-09-1998
Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition
Publisher: MDPI AG
Date: 12-08-2020
DOI: 10.3390/MI11080769
Abstract: Ammonia (NH3)-assisted purification of deposits fabricated by focused electron beam-induced deposition (FEBID) has recently been proven successful for the removal of halide contaminations. Herein, we demonstrate the impact of combined NH3 and electron processing on FEBID deposits containing hydrocarbon contaminations that stem from anionic cyclopentadienyl-type ligands. For this purpose, we performed FEBID using bis(ethylcyclopentadienyl)ruthenium(II) as the precursor and subjected the resulting deposits to NH3 and electron processing, both in an environmental scanning electron microscope (ESEM) and in a surface science study under ultrahigh vacuum (UHV) conditions. The results provide evidence that nitrogen from NH3 is incorporated into the carbon content of the deposits which results in a covalent nitride material. This approach opens a perspective to combine the promising properties of carbon nitrides with respect to photocatalysis or nanosensing with the unique 3D nanoprinting capabilities of FEBID, enabling access to a novel class of tailored nanodevices.
Electron Flux Controlled Switching Between Electron Beam Induced Etching and Deposition
Publisher: Oxford University Press (OUP)
Date: 31-07-2006
DOI: 10.1017/S1431927606069753
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005
Transmission-electron microscopy study of the shape of buried quantum dots
Publisher: American Physical Society (APS)
Date: 15-08-1998
Island shape instabilities and surfactant-like effects in the growth of InGaAs/GaAs quantum dots
Publisher: Elsevier BV
Date: 12-1999
Pure Platinum Nanostructures Grown by Electron Beam Induced Deposition
Publisher: American Chemical Society (ACS)
Date: 25-09-2013
DOI: 10.1021/AM403167D
Abstract: Platinum has numerous applications in catalysis, nanoelectronics, and sensing devices. Here we report a method for localized, mask-free deposition of high-purity platinum that employs a combination of room-temperature, direct-write electron beam induced deposition (EBID) using the precursor Pt(PF3)4, and low temperature (≤400 °C) postgrowth annealing in H2O. The annealing treatment removes phosphorus contaminants through a thermally activated pathway involving dissociation of H2O and the subsequent formation of volatile phosphorus oxides and hydrides that desorb during annealing. The resulting Pt is indistinguishable from pure Pt films by wavelength dispersive X-ray spectroscopy (WDS).
Robust Multicolor Single Photon Emission from Point Defects in Hexagonal Boron Nitride
Publisher: American Chemical Society (ACS)
Date: 18-07-2016
Abstract: Hexagonal boron nitride (hBN) is an emerging two-dimensional material for quantum photonics owing to its large bandgap and hyperbolic properties. Here we report two approaches for engineering quantum emitters in hBN multilayers using either electron beam irradiation or annealing and characterize their photophysical properties. The defects exhibit a broad range of multicolor room-temperature single photon emissions across the visible and the near-infrared spectral ranges, narrow line widths of sub-10 nm at room temperature, and a short excited-state lifetime, and high brightness. We show that the emitters can be categorized into two general groups, but most likely possess similar crystallographic structure. Remarkably, the emitters are extremely robust and withstand aggressive annealing treatments in oxidizing and reducing environments. Our results constitute a step toward deterministic engineering of single emitters in 2D materials and hold great promise for the use of defects in boron nitride as sources for quantum information processing and nanophotonics.
A Light Emitting Diode for Single Photons
Publisher: The Japan Society of Applied Physics
Date: 2003
Electron flux controlled switching between electron beam induced etching and deposition
Publisher: AIP Publishing
Date: 03-2007
DOI: 10.1063/1.2437667
Abstract: Electron beam induced deposition (EBID) and etching (EBIE) are promising methods for the fabrication of three-dimensional nanodevices, wiring of nanostructures, and repair of photolithographic masks. Here, we study simultaneous EBID and EBIE, and demonstrate an athermal electron flux controlled transition between material deposition and etching. The switching is observed when one of the processes has both a higher efficiency and a lower precursor partial pressure than the other. This is demonstrated in two technologically important systems: during XeF2-mediated etching of chrome on a photolithographic mask and during deposition and etching of carbonaceous films on a semiconductor surface. Simultaneous EBID and EBIE can be used to enhance the spatial localization of etch profiles. It plays a key role in reducing contamination buildup rates during low vacuum electron imaging and deposition of high purity nanostructures in the presence of oxygen-containing gases.
Exciton complexes in individual quantum dots as a single-photon source
Publisher: Elsevier BV
Date: 03-2002
Inhibited carrier transfer in ensembles of isolated quantum dots
Publisher: American Physical Society (APS)
Date: 15-12-1999
Dislocation-induced changes in quantum dots: Step alignment and radiative emission
Publisher: AIP Publishing
Date: 19-04-1999
DOI: 10.1063/1.123831
Abstract: A transition between two types of step alignment was observed in a multilayered InGaAs/GaAs quantum-dot (QD) structure. A change to larger QD sizes in smaller concentrations occurred after formation of a dislocation array. Cathodoluminescence (CL) spectra show a bimodal peak with lower energy peak enhancement when probing at lower e-beam energies. The two peaks separate as a result of QD interdiffusion. CL imaging and cross-sectional transmission electron microscopy showed contrast from a dislocation array formed at the interface between GaAs and the first InGaAs QD layer. Strong QD emission in the near infrared (800–1100 nm) was obtained despite the presence of dislocations.
Carrier capture and relaxation in Stranski-KrastanowIn
Publisher:
American Physical Society (APS)
Date:
15-07-2000
Publisher: American Physical Society (APS)
Date: 15-07-2000
Encapsulation-Free Stabilization of Few-Layer Black Phosphorus
Publisher: American Chemical Society (ACS)
Date: 02-07-2018
Abstract: Under ambient conditions and in H
Changes in luminescence intensities and carrier dynamics induced by proton irradiation in
Publisher:
American Physical Society (APS)
Date:
17-12-2002
Publisher: American Physical Society (APS)
Date: 17-12-2002
InGaAs island shapes and adatom migration behavior on (100), (110), (111), and (311) GaAs surfaces
Publisher: AIP Publishing
Date: 15-04-1998
DOI: 10.1063/1.367170
Abstract: The evolution of InGaAs island formation on (100), (110), (111), and (311) GaAs substrates was studied by atomic force microscopy. In addition to determining the growth mode, shape, average size and distribution of InGaAs islands on each orientation, measurement of the saturation island densities enabled an estimation of effective group III adatom surface diffusion lengths. Small lens-shaped islands in addition to larger faceted islands were formed on (100) and (311) surfaces, while trapezoidal and triangular islands were obtained on (110) and (111)B orientations, respectively. Adatom diffusion lengths on these surfaces were found to range from 0.06 μm on (311)B to 3 μm on (111)B.
Robust multicolor single photon emission from point defects in hexagonal boron nitride
Publisher: arXiv
Date: 2016
Continuum models of focused electron beam induced processing
Publisher: Beilstein Institut
Date: 14-07-2015
DOI: 10.3762/BJNANO.6.157
Abstract: Focused electron beam induced processing (FEBIP) is a suite of direct-write, high resolution techniques that enable fabrication and editing of nanostructured materials inside scanning electron microscopes and other focused electron beam (FEB) systems. Here we detail continuum techniques that are used to model FEBIP, and release software that can be used to simulate a wide range of processes reported in the FEBIP literature. These include: (i) etching and deposition performed using precursors that interact with a surface through physisorption and activated chemisorption, (ii) gas mixtures used to perform simultaneous focused electron beam induced etching and deposition (FEBIE and FEBID), and (iii) etch processes that proceed through multiple reaction pathways and generate a number of reaction products at the substrate surface. We also review and release software for Monte Carlo modeling of the precursor gas flux which is needed as an input parameter for continuum FEBIP models.
Stark effect of quantum blue emitters in hBN
Publisher: arXiv
Date: 2022
Kinetics of gas mediated electron beam induced etching
Publisher: AIP Publishing
Date: 21-11-2011
DOI: 10.1063/1.3662928
Abstract: Electron beam induced etching (EBIE) is a high resolution, direct write, chemical dry etch process in which surface-adsorbed precursor molecules are activated by an electron beam. We show that nanoscale EBIE is rate limited through at least two mechanisms ascribed to adsorbate depletion and the transport of gaseous precursor molecules into an etch pit during etching, respectively. The latter has, to date, not been accounted for in models of EBIE and is needed to reproduce etch kinetics which govern the time-evolution of etch pits, EBIE throughput, and spatial resolution.
Robust, directed assembly of fluorescent nanodiamonds
Publisher: arXiv
Date: 2016
Nanostructure Fabrication by Ultra-High-Resolution Environmental Scanning Electron Microscopy
Publisher: American Chemical Society (ACS)
Date: 11-01-2007
DOI: 10.1021/NL062848C
Abstract: Electron beam induced deposition (EBID) is a maskless nanofabrication technique capable of surpassing the resolution limits of resist-based lithography. However, EBID fabrication of functional nanostructures is limited by beam spread in bulk substrates, substrate charging, and delocalized film growth around deposits. Here, we overcome these problems by using environmental scanning electron microscopy (ESEM) to perform EBID and etching while eliminating charging artifacts at the nanoscale. Nanostructure morphology is tailored by slimming of deposits by ESEM imaging in the presence of a gaseous etch precursor and by pre-etching small features into a deposit (using a stationary or a scanned electron beam) prior to a final imaging process. The utility of this process is demonstrated by slimming of nanowires deposited by EBID, by the fabrication of gaps (between 4 and 7 nm wide) in the wires, and by the removal of thin films surrounding such nanowires. ESEM imaging provides a direct view of the slimming process, yielding process resolution that is limited by ESEM image resolution ( approximately 1 nm) and surface roughening occurring during etching.
Our changing nature
Publisher: Springer Science and Business Media LLC
Date: 09-2002
DOI: 10.1038/NMAT721
Changes in carrier dynamics induced by proton irradiation in quantum dots
Publisher: Elsevier BV
Date: 03-2002
Different paths to tunability in III–V quantum dots
Publisher: AIP Publishing
Date: 07-1998
DOI: 10.1063/1.368076
Abstract: Tunability in the concentration and average dimensions of self-forming semiconductor quantum dots (QDs) has been attained. Three of the approaches examined here are: variations with temperature, group V partial pressure and with substrate miscut angle. Thermally activated group III adatom mobilities result in larger diameters and lower concentrations with increasing deposition temperatures. These variations are presented for InGaAs/GaAs and AlInAs/AlGaAs, where striking differences were seen. Tunability in the InGaAs/GaAs QD concentration was also obtained in metalorganic chemical vapor deposition by varying the arsine flow. The latter gave widely varying concentrations and similar sizes. Substrate orientation was found to also be a key factor in island nucleation: Changes in vicinal orientation near (100) can be used to exploit the preferential step edge nucleation at mono and multi-atomic steps, so varying miscut angle (θm) can be used to change island densities and sizes. Anisotropies in island nucleation producing n-dot strings aligned with multiatomic step edges are observed for θm⩾0.75° and up to 2°. Quantum mechanical coupling from such island strings result in non-Gaussian shapes in the inhomogeneously broadened photoluminescence peaks. The effects of some of the other morphological differences presented here on the luminescence emission from QD ground states is discussed for InGaAs/GaAs QDs.
Erratum: Indium Segregation and Enrichment in CoherentIn
Publisher:
American Physical Society (APS)
Date:
09-08-1999
Publisher: American Physical Society (APS)
Date: 09-08-1999
Photon emitting diode using semiconductor quantum dot
Publisher: Opt. Soc. America
Date: 2002
Nanostructure Fabrication by Ultra-high Resolution Environmental Scanning Electron Microscopy
Publisher: Oxford University Press (OUP)
Date: 08-2007
Transmission electron microscopy determination of quantum dot profile
Publisher: IEEE
Date: 1999
Antibacterial activity of silver nanoparticles stabilized on tannin-grafted collagen fiber
Publisher: Elsevier BV
Date: 07-2012
Electron beam induced chemical dry etching and imaging in gaseous NH3environments
Publisher: IOP Publishing
Date: 24-08-2012
DOI: 10.1088/0957-4484/23/37/375302
Abstract: We report the use of ammonia (NH(3)) vapor as a new precursor for nanoscale electron beam induced etching (EBIE) of carbon, and an efficient imaging medium for environmental scanning electron microscopy (ESEM). Etching is demonstrated using amorphous carbonaceous nanowires grown by electron beam induced deposition (EBID). It is ascribed to carbon volatilization by hydrogen radicals generated by electron dissociation of NH(3) adsorbates. The volatilization process is also effective at preventing the buildup of residual hydrocarbon impurities that often compromise EBIE, EBID and electron imaging. We also show that ammonia is a more efficient electron imaging medium than H(2)O, which up to now has been the most commonly used ESEM imaging gas.
Characterization of the northernmost spawning habitat of Dosidicus gigas with implications for its northwards range extension
Publisher: Inter-Research Science Center
Date: 31-05-2017
DOI: 10.3354/MEPS12140
Localization of narrowband single photon emitters in nanodiamonds
Publisher: arXiv
Date: 2016
Enhanced Super-Resolution Imaging of Quantum Emitters in Hexagonal Boron Nitride
Publisher: IEEE
Date: 05-2019
Charged Particle Induced Etching and Functionalization of Two-Dimensional Materials
Publisher: The Electrochemical Society
Date: 03-2022
Abstract: Focused electron beam induced deposition and etching (FEBID and FEBIE) are direct-write nanofabrication techniques in which an electron beam is used to achieve nanostructure functionalization, etching or deposition. Either alone or in combination with in situ plasmas, these techniques can also be used to accelerate reactions that occur in ambient environment, with simultaneous high-resolution imaging. Here, we describe our recent work on etching, functionalization and directed assembly of a range of nano- and two-dimensional materials using temperature-dependent FEBIE experiments in an environmental scanning electron microscope (ESEM). As ex les of the application of these techniques, we demonstrate processes for assembling arrays of nanodiamonds that can be used as magnetic field sensors, as well as for controlled etching of hexagonal boron nitride (hBN) and black phosphorus (BP).
Gas-mediated charged particle beam processing of nanostructured materials
Publisher: SPIE
Date: 06-03-2014
DOI: 10.1117/12.2042021
Silver nanoparticles stabilized by tannin grafted collagen fiber: Synthesis, characterization and antifungal activity
Publisher: Springer Science and Business Media LLC
Date: 03-05-2012
Engineering and localization of quantum emitters in large hexagonal boron nitride layers
Publisher: arXiv
Date: 2016
Evolution of the nanostructure of deposits grown by electron beam induced deposition
Publisher: AIP Publishing
Date: 14-07-2008
DOI: 10.1063/1.2959112
Abstract: Environmental scanning electron microscopy (ESEM) was used to perform electron beam induced deposition (EBID) using a WF6 precursor. The deposits consist of WO3 nanocrystals embedded in an amorphous matrix. Oxide formation is attributed to residual oxidizers present in the ESEM chamber during EBID. Under conditions of fixed low electron flux, the WO3 grain size and the degree of deposit crystallinity increase with time. These changes correlate with the degree of electron energy deposition into the material during growth, indicating that electron beam induced modification of as-grown material is significant in controlling the nanostructure and functionality of materials fabricated by EBID.
Robust, directed assembly of fluorescent nanodiamonds
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR05419F
Abstract: Arrays of fluorescent nanoparticles are highly sought after for applications in sensing, nanophotonics and quantum communications. Here we present a simple and robust method of assembling fluorescent nanodiamonds into macroscopic arrays. Remarkably, the yield of this directed assembly process is greater than 90% and the assembled patterns withstand ultra-sonication for more than three hours. The assembly process is based on covalent bonding of carboxyl to amine functional carbon seeds and is applicable to any material, and to non-planar surfaces. Our results pave the way to directed assembly of sensors and nanophotonics devices.
High resolution radially symmetric nanostructures from simultaneous electron beam induced etching and deposition
Publisher: IOP Publishing
Date: 06-12-2007
DOI: 10.1088/0957-4484/19/02/025303
Abstract: Electron beam induced etching (EBIE) and deposition (EBID) are promising fabrication techniques in which an electron beam is used to dissociate surface-adsorbed precursor molecules to achieve etching or deposition. Spatial resolution is normally limited by the electron flux distribution at the substrate surface. Here we present simultaneous EBIE and EBID (EBIED) as a method for surpassing this resolution limit by using adsorbate depletion to induce etching and deposition in adjacent regions within the electron flux profile. Our simulation results indicate the possibility of growth control of radially symmetric nanostructures at the sub-1 nm length scale on bulk substrates. The technique is well suited to the fabrication of ring-shaped nanostructures such as those employed in plasmonics, sensing devices, magneto-optics and magnetoelectronics.
Super-resolution imaging of quantum emitters in layered materials
Publisher: arXiv
Date: 2017
Photophysics of blue quantum emitters in hexagonal boron nitride
Publisher: IOP Publishing
Date: 03-2023
Abstract: Colour centres in hexagonal boron nitride (hBN) have emerged as intriguing contenders for integrated quantum photonics. In this work, we present a detailed photophysical analysis of hBN single emitters emitting at the blue spectral range. The emitters are fabricated by different electron beam irradiation and annealing conditions and exhibit narrow-band luminescence centred at 436 nm. Photon statistics as well as rigorous photodynamics analysis unveils potential level structure of the emitters, which suggests lack of a metastable state, supported by a theoretical analysis. The potential defect can have an electronic structure with fully occupied defect state in the lower half of the hBN band gap and empty defect state in the upper half of the band gap. Overall, our results are important to understand the photophysical properties of the emerging family of blue quantum emitters in hBN as potential sources for scalable quantum photonic applications.
Electron-Beam-Induced Deposition as a Technique for Analysis of Precursor Molecule Diffusion Barriers and Prefactors
Publisher: American Chemical Society (ACS)
Date: 15-09-2015
Abstract: Electron-beam-induced deposition (EBID) is a direct-write chemical vapor deposition technique in which an electron beam is used for precursor dissociation. Here we show that Arrhenius analysis of the deposition rates of nanostructures grown by EBID can be used to deduce the diffusion energies and corresponding preexponential factors of EBID precursor molecules. We explain the limitations of this approach, define growth conditions needed to minimize errors, and explain why the errors increase systematically as EBID parameters erge from ideal growth conditions. Under suitable deposition conditions, EBID can be used as a localized technique for analysis of adsorption barriers and prefactors.
Ambient Protection of Few-Layer Black Phosphorus via Sequestration of Reactive Oxygen Species
Publisher: Wiley
Date: 12-05-2017
Abstract: Few-layer black phosphorous (BP) has emerged as a promising candidate for next-generation nanophotonic and nanoelectronic devices. However, rapid ambient degradation of mechanically exfoliated BP poses challenges in its practical deployment in scalable devices. To date, the strategies employed to protect BP have relied upon preventing its exposure to atmospheric conditions. Here, an approach that allows this sensitive material to remain stable without requiring its isolation from the ambient environment is reported. The method draws inspiration from the unique ability of biological systems to avoid photo-oxidative damage caused by reactive oxygen species. Since BP undergoes similar photo-oxidative degradation, imidazolium-based ionic liquids are employed as quenchers of these damaging species on the BP surface. This chemical sequestration strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics. This study opens opportunities to practically implement BP and other environmentally sensitive 2D materials for electronic applications.
Intermixing induced changes in the radiative emission from III–V quantum dots
Publisher: AIP Publishing
Date: 06-1998
DOI: 10.1063/1.121478
Abstract: We have examined the effect of thermally induced interdiffusion on the luminescence emission from red and infrared emitting self-assembled III–V quantum dots. Three different combinations of dot/barrier materials have been investigated: InAlAs/AlGaAs, InGaAs/AlGaAs and InGaAs/GaAs. In all cases, thermal intermixing was found to result in significant blueshifts of the photoluminescence (PL) emission. In addition, narrowing of the linewidth of the inhomogeneously broadened PL peak was observed. Both effects were found to be strongly dependent on the material system and average dot size. InAlAs/AlGaAs quantum dots exhibited the greatest linewidth reduction after intermixing, indicating this to be a promising method of achieving narrower luminescence lines for devices such as red-emitting zero-dimensional lasers.
Role of Activated Chemisorption in Gas-Mediated Electron Beam Induced Deposition
Publisher: American Physical Society (APS)
Date: 03-10-2012
Contamination-free imaging by electron induced carbon volatilization in environmental scanning electron microscopy
Publisher: AIP Publishing
Date: 08-2009
DOI: 10.1063/1.3187926
Abstract: Many ultraviolet, x-ray and charged particle beam techniques are inhibited by the growth of carbonaceous films caused by cross linking of hydrocarbon contaminant adsorbates. In electron microscopy, such films obscure surface features and reduce resolution. We demonstrate how resolution degradation can be alleviated using a H2O environment via gas mediated, electron beam induced carbon volatilization, a process that competes with film growth. Net behavior is a function of electron flux, which provides control over growth kinetics during imaging. Under optimized conditions, film growth can be eliminated, removing contamination as a factor limiting image information content and resolution.
Indium segregation and enrichment in coherent InxGa1-x As/GaAs quantum dots
Publisher: American Physical Society (APS)
Date: 21-06-1999
Sodalite-type Na8Mg3Si9O24(OH)2 and Na8Mg3Si9O24(OH,Cl)2: novel framework magnesiosilicates
Publisher: Royal Society of Chemistry (RSC)
Date: 1996
DOI: 10.1039/JM9960601933
Engineering and Localization of Quantum Emitters in Large Hexagonal Boron Nitride Layers
Publisher: American Chemical Society (ACS)
Date: 20-10-2016
Abstract: Hexagonal boron nitride is a wide-band-gap van der Waals material that has recently emerged as a promising platform for quantum photonics experiments. In this work, we study the formation and localization of narrowband quantum emitters in large flakes (up to tens of micrometers wide) of hexagonal boron nitride. The emitters can be activated in as-grown hexagonal boron nitride by electron irradiation or high-temperature annealing, and the emitter formation probability can be increased by ion implantation or focused laser irradiation of the as-grown material. Interestingly, we show that the emitters are always localized at the edges of the flakes, unlike most luminescent point defects in three-dimensional materials. Our results constitute an important step on the roadmap of deploying hexagonal boron nitride in nanophotonics applications.
Time Resolved Studies of Proton Irradiated Quantum Dots
Publisher: Springer Science and Business Media LLC
Date: 2002
Abstract: The effects of proton irradiation on carrier dynamics were measured by time-resolved photoluminescence on InGaAs/GaAs quantum dot structures with different dot density and substrate orientation, as well as on InAlAs/AlGaAs quantum dots. Results were compared to irradiation effects on carrier dynamics in thin InGaAs quantum wells. We find that carrier lifetimes in QDs are much less affected by proton irradiation than in quantum wells, which can be attributed to the three-dimensional carrier confinement in quantum dots.
Black Phosphorus: Ambient Protection of Few-Layer Black Phosphorus via Sequestration of Reactive Oxygen Species (Adv. Mater. 27/2017)
Publisher: Wiley
Date: 07-2017
Effects of oxygen on electron beam induced deposition of SiO2 using physisorbed and chemisorbed tetraethoxysilane
Publisher: AIP Publishing
Date: 19-11-2012
DOI: 10.1063/1.4767521
Abstract: Electron beam induced deposition (EBID) is limited by low throughput and purity of as-grown material. Co-injection of O2 with the growth precursor is known to increase both the purity and deposition rate of materials such as SiO2 at room temperature. Here, we show that O2 inhibits rather than enhances EBID from tetraethoxysilane (TEOS) precursor at elevated temperatures. This behavior is attributed to surface site competition between chemisorbates at elevated temperature, and TEOS decomposition by atomic oxygen produced through electron dissociation of physisorbed O2 at room temperature.
A catalogue of velocities in the cluster of galaxies Abell 85
Publisher: EDP Sciences
Date: 04-1998
DOI: 10.1051/AAS:1998185
Localization of Narrowband Single Photon Emitters in Nanodiamonds
Publisher: American Chemical Society (ACS)
Date: 11-03-2016
Abstract: Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bioimaging. However, current understanding of the origin of these emitters is extremely limited. In this work, we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in in idual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine in idual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond and are directly relevant to fabrication of novel quantum optics devices and sensors.
One-Step Nanoscale Patterning of Silver Nanowire–Nitride Heterostructures Using Substrate-Assisted Chemical Etching
Publisher: American Chemical Society (ACS)
Date: 13-12-2018
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Nature Publishing Group
Location: United Kingdom of Great Britain and Northern Ireland
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Location: United Kingdom of Great Britain and Northern Ireland
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