ORCID Profile
0000-0002-1304-4219
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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)
Nanotechnology | Nanotechnology | Condensed Matter Physics | Condensed Matter Physics—Structural Properties | Condensed Matter Physics—Electronic And Magnetic Properties; | Optics And Opto-Electronic Physics | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Electrical and Electronic Engineering | Materials Engineering Not Elsewhere Classified | Microelectronics and Integrated Circuits | Nanoscale Characterisation | Optical Physics | Functional Materials | Integrated Circuits | Other Electronic Engineering | Elemental Semiconductors | Materials Engineering | Photonics, Optoelectronics and Optical Communications | Interdisciplinary Engineering Not Elsewhere Classified | Nanofabrication, Growth and Self Assembly | Atomic, Molecular, Nuclear, Particle and Plasma Physics | Surface properties of condensed matter | Colloid And Surface Chemistry | Manufacturing Engineering Not Elsewhere Classified | Nanotechnology | Nanofabrication growth and self assembly | Instruments And Techniques | Functional materials | Compound Semiconductors | Condensed Matter Physics—Other | Solid State Chemistry | Mathematical Physics | Optical And Photonic Systems | Nanophotonics | Petrophysics | Nanomaterials | Surfaces and Structural Properties of Condensed Matter | Nuclear And Particle Physics | Condensed Matter Characterisation Technique Development | Physical Sciences Not Elsewhere Classified
ANZSRC Socio-Economic Objective (SEO)
Physical sciences | Integrated circuits and devices | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Higher education | Expanding Knowledge in Technology | Other | Solar-photoelectric | Ceramics | Scientific instrumentation | Communication equipment not elsewhere classified | Combined operations | Biological sciences | Earth sciences | Network transmission equipment | Chemical sciences | Other | Manufactured products not elsewhere classified | Computer equipment | Solar-Photovoltaic Energy | Machinery and equipment not elsewhere classified |
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Publications
Crystal size and oxygen segregation for polycrystalline GaN
Publisher: AIP Publishing
Date: 27-08-2002
DOI: 10.1063/1.1499232
Abstract: The grain size for polycrystalline GaN, grown in low-temperature gallium-rich conditions, is shown to be correlated to the oxygen content of the films. Films with lower oxygen content were observed to have larger crystals with an increased tendency to a single-preferred crystal orientation. Elastic recoil detection analysis with heavy ions (i.e., 200 MeV Au 197 ions) was used to determine the composition of the GaN films grown for the study, including the hydrogen, carbon, gallium, nitrogen, and oxygen content. Atomic force microscopy and x-ray diffraction were used to study the s le morphology. From these measurements, the available surface area of the films was found to be sufficient for a significant proportion of the oxygen present in the films to segregate at the grain boundaries. This interpretation is consistent with earlier theoretical studies of the formation and segregation of the VGa-(ON)3 defect complex at dislocation sites in gallium-rich GaN. For this work, however, the defect complex is believed to segregate at the grain boundary of the polycrystalline GaN.
Diamond structure recovery during ion irradiation at elevated temperatures
Publisher: Elsevier BV
Date: 12-2015
Determination of composition, thickness and growth rate profiles of MOCVD grown Hg-xCdxTe
Publisher: Elsevier BV
Date: 07-1993
Anatomy of filamentary threshold switching in amorphous niobium oxide
Publisher: IOP Publishing
Date: 11-07-2018
Abstract: The threshold switching behavior of Pt/NbO
Understanding composite negative differential resistance in niobium oxide memristors
Publisher: IOP Publishing
Date: 07-12-2021
Abstract: Volatile memristors, or threshold switching devices, exhibit a erse range of negative differential resistance (NDR) characteristics under current-controlled operation and understanding the origin of these responses is of great importance for exploring their potential as nano-scale oscillators for neuromorphic computing. Here we use a previously developed two-zone, parallel memristor model to undertake a systematic analysis of NDR modes in two-terminal metal-oxide-metal devices. The model assumes that the non-uniform current distribution associated with filamentary conduction can be represented by a high current density core and a lower current-density shell where the core is assumed to have a memristive response due to Poole-Frenkel conduction and the shell is represented by either a fixed resistor or a second memristive region. A detailed analysis of the electrical circuits is undertaken using a lumped-element thermal model of the core-shell structure, and is shown to reproduce continuous and discontinuous NDR responses, as well as more complex compound behaviour. Finally, an interesting double-window oscillation behaviour is predicted and experimentally verified for a device with compound NDR behaviour. These results clearly identify the origin of different NDR responses and provide a strong basis for designing devices with complex NDR characteristics.
Study of MOCVD grown Hg1−xCdxTe by ion beam techniques
Publisher: Elsevier BV
Date: 06-1993
Current Localization and Redistribution as the Basis of Discontinuous Current Controlled Negative Differential Resistance in NbO x
Publisher: Wiley
Date: 09-10-2019
Linear optical properties of Ge nanocrystals in silica
Publisher: AIP Publishing
Date: 08-10-2001
DOI: 10.1063/1.1409591
Abstract: The absorption and extinction spectra of Ge nanocrystals in silica formed by ion implantation are studied using photothermal deflection and transmission spectroscopies. It is found that scattering makes a significant contribution to the extinction spectrum, d ing the spectral features and resulting in a Rayleigh scattering-like ω4 dependence. In contrast, the spectra measured by photothermal deflection clearly show features such as the E1/E1+Δ1 transitions. The Tauc gap is extracted to be ∼0.7±0.1 eV.
Imaging of the relative saturation current density and sheet resistance of laser doped regions via photoluminescence
Publisher: AIP Publishing
Date: 06-08-2013
DOI: 10.1063/1.4817525
Abstract: We present an approach to characterize the relative saturation current density (Joe) and sheet resistance (RSH) of laser doped regions on silicon wafers based on rapid photoluminescence (PL) imaging. In the absence of surface passivation layers, the RSH of laser doped regions using a wide range of laser parameters is found to be inversely proportional to the PL intensity (IPL). We explain the underlying mechanism for this correlation, which reveals that, in principle, IPL is inversely proportional to Joe at any injection level. The validity of this relationship under a wide range of typical experimental conditions is confirmed by numerical simulations. This method allows the optimal laser parameters for achieving low RSH and Joe to be determined from a simple PL image.
Coupling dynamics of Nb/Nb2O5relaxation oscillators
Publisher: IOP Publishing
Date: 20-02-2017
Abstract: The coupling dynamics of capacitively coupled Nb/Nb
Effect of rhenium irradiations on the mechanical properties of tungsten for nuclear fusion applications
Publisher: Elsevier BV
Date: 08-2016
Understanding modes of negative differential resistance in amorphous and polycrystalline vanadium oxides
Publisher: AIP Publishing
Date: 23-12-2020
DOI: 10.1063/5.0027875
Abstract: Metal–oxide–metal devices based on amorphous VOx are shown to exhibit one of two distinct negative differential resistance (NDR) characteristics depending on the maximum current employed for electroforming. For low compliance currents they exhibit a smooth S-type characteristic and have a temperature-dependent device resistance characterized by an activation energy of 0.25 eV, consistent with conduction in polycrystalline VO2, while for high compliance currents they exhibit an abrupt snap-back characteristic and a resistance characterized by an activation energy of 0.025 eV, consistent with conduction in oxygen deficient VOx. In both cases, the temperature dependence of the switching voltage implies that the conductivity change is due to the insulator–metal transition in VO2. From this analysis, it is concluded that electroforming at low currents creates a conductive filament comprised largely of polycrystalline VO2, while electroforming at high currents creates a composite structure comprised of VO2 and a conductive halo of oxygen deficient VOx. The effect of electroforming on the NDR mode is then explained with reference to a lumped element model of filamentary conduction that includes the effect of a parallel resistance created by the halo. These results provide new insight into the NDR response of vanadium-oxide-based devices and a basis for designing devices with specific characteristics.
Gallium and oxygen accumulations on gallium nitride surfaces following argon ion milling in ultra-high vacuum conditions
Publisher: Elsevier BV
Date: 05-2004
Thermal Conductivity of Amorphous NbOx Thin Films and Its Effect on Volatile Memristive Switching
Publisher: American Chemical Society (ACS)
Date: 29-04-2022
Abstract: Metal-oxide-metal (MOM) devices based on niobium oxide exhibit threshold switching (or current-controlled negative differential resistance) due to thermally induced conductivity changes produced by Joule heating. A detailed understanding of the device characteristics therefore relies on an understanding of the thermal properties of the niobium oxide film and the MOM device structure. In this study, we use time-domain thermoreflectance to determine the thermal conductivity of amorphous NbO
Temperature dependence of blistering in hydrogen implanted Si and Ge
Publisher: Elsevier BV
Date: 07-2013
Temperature dependent frequency tuning of NbOx relaxation oscillators
Publisher: AIP Publishing
Date: 13-11-2017
DOI: 10.1063/1.4999373
Abstract: This study investigates the temperature dependence of current-controlled negative differential resistance (CC-NDR) in Pt/NbOx/TiN devices and its effect on the dynamics of associated Pearson-Anson relaxation oscillators. The voltage range over which CC-NDR is observed decreases with increasing temperature such that no NDR is observed for temperatures above ∼380 K. Up to this temperature, relaxation oscillators exhibit voltage and temperature dependent oscillation frequencies in the range of 1 to 13 MHz. Significantly, the sensitivity of the frequency to temperature changes was found to be voltage-dependent, ranging from 39.6 kHz/K at a source voltage of 2 V to 110 kHz/K at a source voltage of 3 V, in the temperature range of 296–328 K. Such a behaviour provides insights into temperature tolerance and tuning variability for environmentally sensitive neuromorphic computing.
The fabrication and properties of silicon-nanocrystal-based devices and structures produced by ion implantation – The search for gain
Publisher: Elsevier BV
Date: 05-2003
Rapid, substrate-independent thickness determination of large area graphene layers
Publisher: AIP Publishing
Date: 05-12-2011
DOI: 10.1063/1.3664633
Abstract: Phase-shifting interferometric imaging is shown to be a powerful analytical tool for studying graphene films, providing quantitative analysis of large area s les with an optical thickness resolution of ≤0.05 nm. The technique is readily able to identify single sheets of graphene and to quantitatively distinguish between layers composed of multiple graphene sheets. The thickness resolution of the technique is shown to result from the phase shift produced by a graphene film as incident and reflected light pass through it, rather than from path-length differences produced by surface height variations. This is enhanced by the high refractive index of graphene, estimated in this work to be nG = 2.99 ± 0.18.
Proceedings of the 20th International Conference on Ion Beam Modification of Materials (IBMM 2016)
Publisher: Elsevier BV
Date: 10-2017
Characterization of low-temperature MOCVD Cd1−xMnxTe thin films
Publisher: Elsevier BV
Date: 1991
Threshold current reduction for the metal–insulator transition in NbO2−x-selector devices: the effect of ReRAM integration
Publisher: IOP Publishing
Date: 20-03-2015
Nanomechanical properties of sputter-deposited HfO2 and HfxSi1-xO2 thin films
Publisher: AIP Publishing
Date: 15-08-2011
DOI: 10.1063/1.3627155
Abstract: The mechanical properties of sputter-deposited HfO2 and HfxSi1-xO2 films were studied as a function of composition using nanoindentation. The elastic modulus and hardness were measured at room temperature for as-deposited films of varying Hf content and for films subjected to annealing at 1000 °C. The elastic modulus and hardness of as-deposited films were found to increase monotonically with increasing HfO2 content, with the hardness increasing from 5.0 ± 0.3 GPa for pure SiO2 to 8.4 ± 0.4 GPa for pure HfO2. All films were found to be harder after annealing at 1000 °C, with the increase for SiO2 films attributed to densification of the SiO2 network and that for the HfxSi1-xO2 films to a combination of phase separation, densification, and crystallization.
Metal-oxide interface reactions and their effect on integrated resistive/threshold switching in NbO x
Publisher: IOP Publishing
Date: 19-03-2020
Engineering the Threshold Switching Response of Nb2O5-Based Memristors by Ti Doping
Publisher: American Chemical Society (ACS)
Date: 07-01-2021
Resistive switching behavior in HfO<inf>2</inf> with Nb as an oxygen exchange layer
Publisher: IEEE
Date: 12-2014
Finite element modeling of resistive switching in Nb<inf>2</inf>O<inf>5</inf>-based memory device
Publisher: IEEE
Date: 12-2014
Oxygen diffusion in TiO 2 films studied by electron and ion Rutherford backscattering
Publisher: Elsevier BV
Date: 05-2017
Effect of Microstructure on Dielectric Breakdown in Amorphous HfO2 Films
Publisher: Oxford University Press (OUP)
Date: 08-2014
Modification, Synthesis, and Analysis of Advanced Materials Using Ion Beam Techniques
Publisher: Hindawi Limited
Date: 2012
DOI: 10.1155/2012/431297
Temperature dependence of threshold switching in NbO<inf>x</inf> thin films
Publisher: IEEE
Date: 12-2014
Self-assembly of an NbO2 interlayer and configurable resistive switching in Pt/Nb/HfO2/Pt structures
Publisher: AIP Publishing
Date: 28-09-2015
DOI: 10.1063/1.4932096
Abstract: A configurable resistive switching response is reported for Pt/Nb/HfO2/Pt devices subjected to different set compliance currents. When operated at a low compliance-current (∼100 μA), devices show uniform bipolar resistive switching behavior. As the compliance current is increased (∼500 μA), the switching mode changes to integrated threshold-resistive (1S1M) switching, and at still higher currents (∼1 mA), it changes to symmetric threshold switching (1S) characteristic of threshold switching in NbO2−δ. These switching transitions are shown to be consistent with the development of an NbO2−δ interlayer at the Nb/HfO2 interface that is limited by the set compliance current due to its effect on oxygen transport and local Joule heating. The proposed mechanism is supported by finite element modeling of the 1S1M response assuming the presence of such an interlayer. These findings help to understand role of interface reactions in controlling device performance and provide a means for the self-assembly of integrated 1S1M resistive random access memory structures.
Effect of W self-implantation and He plasma exposure on early-stage defect and bubble formation in tungsten
Publisher: IOP Publishing
Date: 18-04-2018
Influence of implantation damage on emitter recombination
Publisher: Elsevier BV
Date: 2014
Unconventional magnetism in all-carbon nanofoam
Publisher: American Physical Society (APS)
Date: 17-08-2004
Using doping superlattices to study transient-enhanced diffusion of boron in regrown silicon
Publisher: AIP Publishing
Date: 27-05-1996
DOI: 10.1063/1.116439
Abstract: A boron-doped silicon superlattice consisting of three boron spikes separated by 1700 Å of undoped silicon has been grown by molecular beam epitaxy and used to study the evolution of point defects following an amorphizing implant of Si+. After MBE growth, the wafer was implanted at 77 K with either 146 or 292 keV Si+ at a dose of 5×1015/cm2. These implants produced amorphous layer depths that coincided with the depths of either the middle B peak or just below the deepest B peak. The s les were then annealed at 800 °C in an Ar ambient. Secondary-ion-mass spectrometry and transmission electron microscopy were used to monitor the diffusion of the boron spikes upon annealing and the evolution of the extended defects upon annealing, respectively. For the lower-energy s le, an enhancement in the B diffusivity of over 500× was observed for both the surface B spike and the deepest B spike. The higher-energy implant shows conclusively that the back flow of interstitials into the regrown region is coming from the end-of-range damage just below the amorphous/crystalline interface. These results show that for these implant conditions the end-of-range damage does not act as a barrier to flow of interstitials to the surface. In addition it is noted that boron in the regrown silicon does not cluster whereas the boron below the amorphous crystalline interface does. Both of these features must be accounted for when modeling boron diffusion in regrown silicon.
Physical and optical characterisation of Ge-implanted silica
Publisher: Elsevier BV
Date: 04-2001
Hydrogen platelet evolution in mechanically strained silicon
Publisher: IEEE
Date: 12-2010
Origin of Current‐Controlled Negative Differential Resistance Modes and the Emergence of Composite Characteristics with High Complexity
Publisher: Wiley
Date: 28-08-2019
Optical emission from erbium-doped silica nanowires
Publisher: AIP Publishing
Date: 15-05-2008
DOI: 10.1063/1.2924420
Abstract: Infrared optical emission from erbium-doped silica nanowires is shown to have property characteristic of the material nanostructure and to provide the basis for the fabrication of integrated photonic devices and biosensors. Silica nanowires of approximately 150 nm diameter were grown on a silicon wafer by metal-induced growth using a thin (20 nm) sputter-deposited palladium layer as a catalyst. The resulting wires were then ion implanted with 110 keV ErO− ions and annealed at 900 °C to optically activate the erbium. These wires exhibited photoluminescence emission at 1.54 μm, characteristic of the I415/2−I413/2 transition in erbium however, comparison to similarly implanted fused silica layers revealed stronger thermal quenching and longer luminescence lifetimes in the nanowire s les. The former is attributed to an increase in defect-induced quenching partly due to the large surface-volume ratio of the nanowires, while the latter is attributed to a reduction in the optical density of states associated with the nanostructure morphology. Details of this behavior are discussed together with the implications for potential device applications.
High performance bulk photovoltaics in narrow-bandgap centrosymmetric ultrathin films
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9MH01744E
Abstract: Intensive bulk photovoltaic effects are produced in narrow-bandgap centrosymmetric materials by a new strategy based on polar nano-regions.
Oxygen Self-Diffusion inHfO 2 Publisher:
American Physical Society (APS)
Date:
30-04-2014
Publisher: American Physical Society (APS)
Date: 30-04-2014
Mechanical properties of tungsten following rhenium ion and helium plasma exposure
Publisher: Elsevier BV
Date: 08-2017
Neuropsychiatry: A synthesis of clinical and scientific fields for disorders of mind and body
Publisher: SAGE Publications
Date: 25-11-2016
Formation of ordered arrays of gold particles by nanoindentation templating
Publisher: Wiley
Date: 22-10-2013
Ion beam synthesis and doping of photonic nanostructures
Publisher: Elsevier BV
Date: 04-2008
Determination of thickness and composition of high-k dielectrics using high-energy electrons
Publisher: AIP Publishing
Date: 12-08-2013
DOI: 10.1063/1.4818637
Abstract: We demonstrate the application of high-energy elastic electron backscattering to the analysis of thin (2–20 nm) HfO2 overlayers on oxidized Si substrates. The film composition and thickness are determined directly from elastic scattering peaks characteristic of each element. The stoichiometry of the films is determined with an accuracy of 5%–10%. The experimental results are corroborated by medium energy ions scattering and Rutherford backscattering spectrometry measurements, and clearly demonstrate the applicability of the technique for thin-film analysis. Significantly, the presented technique opens new possibilities for nm depth profiling with high spatial resolution in scanning electron microscopes.
Erbium emission from nanoengineered silicon surface
Publisher: American Chemical Society (ACS)
Date: 04-12-2008
DOI: 10.1021/JP808462J
Isotopically Enriched10BN Nanotubes
Publisher: Wiley
Date: 18-08-2006
Detection and spatial mapping of conductive filaments in metal/oxide/metal cross-point devices using a thin photoresist layer
Publisher: AIP Publishing
Date: 11-02-2019
DOI: 10.1063/1.5084060
Abstract: A simple means of detecting and spatially mapping volatile and nonvolatile conductive filaments in metal/oxide/metal cross-point devices is introduced, and its application demonstrated. The technique is based on thermal discolouration of a thin photoresist layer deposited on the top electrode (TE) of the cross-point device and relies on the increase in temperature produced by local Joule heating of an underlying conductive filament. Finite element modelling of the temperature distribution and its dependencies shows that the maximum temperature at the TE hotoresist interface is particularly sensitive to the TE thickness. The technique is demonstrated on NbOx-based metal-oxide-metal cross-point devices with a 25 nm thick top (Pt) electrode, where it is used to undertake a statistical analysis of the filament location as a function of device area. This shows that filament formation is heterogeneous the majority of filaments form preferentially along the TE edge, and the fraction of these increases with the decreasing device area. Transmission electron microscopy of the top and bottom electrode edges is used to explain this observation and suggests that it is due to a reduction in the effective oxide thickness in this region.
Forming-free bipolar resistive switching and quantum conductance in NiO/FTO structures
Publisher: IOP Publishing
Date: 04-09-2019
Threshold switching and electrical self-oscillation in niobium oxide films
Publisher: AIP Publishing
Date: 28-09-2016
DOI: 10.1063/1.4963288
Abstract: Electrical self-sustained oscillations have been observed in a broad range of two-terminal systems and are of interest as possible building blocks for bio-inspired neuromorphic computing. In this work, we experimentally explore voltage-controlled oscillations in NbOx devices with a particular focus on understanding how the frequency and waveform are influenced by circuit parameters. We also introduce a finite element model of the device based on a Joule-heating induced insulator-metal transition. The electroformed device structure is represented by a cylindrical conductive channel (filament) comprised of NbO/NbO2 zones and surrounded by an Nb2O5−x matrix. The model is shown to reproduce the current-controlled negative differential resistance observed in measured current-voltage curves, and is combined with circuit elements to simulate the waveforms and dynamics of an isolated Pearson–Anson oscillator. Such modeling is shown to provide considerable insight into the relationship between the material response and device and circuit characteristics.
Physical Origin of Negative Differential Resistance in V3O5 and Its Application as a Solid‐State Oscillator
Publisher: Wiley
Date: 30-12-2022
Abstract: Oxides that exhibit an insulator–metal transition can be used to fabricate energy‐efficient relaxation oscillators for use in hardware‐based neural networks but there are very few oxides with transition temperatures above room temperature. Here the structural, electrical, and thermal properties of V 3 O 5 thin films and their application as the functional oxide in metal/oxide/metal relaxation oscillators are reported. The V 3 O 5 devices show electroforming‐free volatile threshold switching and negative differential resistance (NDR) with stable ( % variation) cycle‐to‐cycle operation. The physical mechanisms underpinning these characteristics are investigated using a combination of electrical measurements, in situ thermal imaging, and device modeling. This shows that conduction is confined to a narrow filamentary path due to self‐confinement of the current distribution and that the NDR response is initiated at temperatures well below the insulator–metal transition temperature where it is dominated by the temperature‐dependent conductivity of the insulating phase. Finally, the dynamics of in idual and coupled V 3 O 5 ‐based relaxation oscillators is reported, showing that capacitively coupled devices exhibit rich non‐linear dynamics, including frequency and phase synchronization. These results establish V 3 O 5 as a new functional material for volatile threshold switching and advance the development of robust solid‐state neurons for neuromorphic computing.
Boron implanted, laser annealed p+ emitter for n-type interdigitated back-contact solar cells
Publisher: Elsevier BV
Date: 2014
The composition, structure and properties of four different glassy carbons
Publisher: Elsevier BV
Date: 10-2019
Reduced Threshold Current in NbO2 Selector by Engineering Device Structure
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2014
Activation Energy and Blistering Rate in Hydrogen-implanted Semiconductors
Publisher: Springer Science and Business Media LLC
Date: 2012
DOI: 10.1557/OPL.2012.677
Abstract: Hydrogen blister rates in Si (100), Si (111) and Ge (100) substrates are compared as a function of annealing temperature and time, for a range of implant energies and fluences. For each material, the rate of blister formation was found to exhibit Arrhenius behavior and to be characterised by a single activation energy over the temperature range examined. The extracted activation energies were 2.28±0.03 eV, 2.17±0.06 eV and 1.4±0.03 eV for (100) Si (111) Si and (100) Ge, respectively. These results are compared with reported measurements and discussed in relation to proposed models of hydrogen blistering.
Thermal transport in metal-NbOx-metal cross-point devices and its effect on threshold switching characteristics
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3NR00173C
Abstract: The thickness and thermal conductivity of electrodes are shown to have a direct impact on the volatile threshold switching characteristics of NbO x -based memristors due to their effect on the temperature of the active volume.
Nonvolatile memories using deep traps formed in Al2O3 by metal ion implantation
Publisher: AIP Publishing
Date: 16-03-2009
DOI: 10.1063/1.3097799
Abstract: We demonstrate the feasibility of an approach to nonvolatile memory (NVM) that exploits charge trapping at deep-energy levels formed in Al2O3 by metal doping. Our calculations show that V and Nb are expected to form such deep energy levels in the band gap of Al2O3. To demonstrate the effectiveness of this approach these metal ions were ion-implanted into test structures based on an Al2O3 trapping layer. Several structural analysis techniques and photocurrent spectroscopy show that the doped metal ions are located close to the Al2O3/SiO2 interface and exhibit characteristics consistent with some of the deep levels predicted in calculations. The resulting test devices are shown to exhibit promising NVM characteristics.
The effect of annealing ambient on carrier recombination in boron implanted silicon
Publisher: Wiley
Date: 13-08-2014
MeV implantation into semiconductors
Publisher: Elsevier BV
Date: 06-1993
Elasto-plastic characterisation of low-temperature plasma-deposited silicon nitride thin films using nanoindentation
Publisher: Inderscience Publishers
Date: 2009
Room temperature synthesis of HfO2/HfO x heterostructures by ion-implantation
Publisher: IOP Publishing
Date: 15-08-2018
Abstract: Implantation of Hf films with oxygen ions is shown to be an effective means of fabricating high-quality HfO
Nonvolatile memories using deep traps formed in HfO2 by Nb ion implantation
Publisher: AIP Publishing
Date: 03-2011
DOI: 10.1063/1.3554444
Abstract: We report nonvolatile memories (NVMs) based on deep-energy trap levels formed in HfO2 by metal ion implantation. A comparison of Nb- and Ta-implanted s les shows that suitable charge-trapping centers are formed in Nb-implanted s les, but not in Ta-implanted s les. This is consistent with density-functional theory calculations which predict that only Nb will form deep-energy levels in the bandgap of HfO2. Photocurrent spectroscopy exhibits characteristics consistent with one of the trap levels predicted in these calculations. Nb-implanted s les showing memory windows in capacitance–voltage (V) curves always exhibit current (I) peaks in I–V curves, indicating that NVM effects result from deep traps in HfO2. In contrast, Ta-implanted s les show dielectric breakdowns during the I–V sweeps between 5 and 11 V, consistent with the fact that no trap levels are present. For a s le implanted with a fluence of 1013 Nb cm−2, the charge losses after 104 s are ∼9.8 and ∼25.5% at room temperature (RT) and 85°C, respectively, and the expected charge loss after 10 years is ∼34% at RT, very promising for commercial NVMs.
Optical absorption measurements of silica containing Si nanocrystals produced by ion implantation and thermal annealing
Publisher: AIP Publishing
Date: 25-02-2002
DOI: 10.1063/1.1454217
Abstract: Optical absorption spectra from silicon-implanted silica slides are shown to contain features due to optical interference. These features, which result from the modified refractive index profile produced by the implant, can readily lead to misinterpretation of absorption spectra. To demonstrate the importance of such effects, silica s les were implanted with 80, 400, and 600 keV Si ions to fluences in the range 0.6–3.0×1017 Si.cm−2 and annealed at 1100 °C for 1 h to form Si nanocrystals. Optical absorption/transmittance spectra from these s les show considerable structure that is characteristic of the particular implant conditions. This structure is shown to correlate with the transmittance of the s les as calculated from the modified refractive index profile for each implant. The lack of such structure in absorption spectra measured by photodeflection spectrometry is used to confirm this interpretation.
Super-resolution optical imaging of binary colloidal assemblies
Publisher: Inderscience Publishers
Date: 2014
Low-Variance Memristor-Based Multi-Level Ternary Combinational Logic
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2022
Nonvolatile-Memory Characteristics of $\hbox{AlO}^{-}$ -Implanted $\hbox{Al}_{2}\hbox{O}_{3}$
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2009
A high-energy electron scattering study of the electronic structure and elemental composition of O-implanted Ta films used for the fabrication of memristor devices
Publisher: AIP Publishing
Date: 20-08-2013
DOI: 10.1063/1.4818524
Abstract: High-energy electron scattering is used to investigate Ta films implanted with 10 keV O ions. These films are of interest as they have been used for the fabrication of memristors. High-energy electron scattering is used with incoming electron energies ranging from 5 to 40 keV. The inelastic mean free path, and hence the probing depth, is at these energies of the same order as the range of the implanted ions. At the same time, we can distinguish the mass of the atom that scattered the electron elastically, due to the dependence of the recoil energy on the mass of the scatterer. This allows us to determine quantitatively the atomic composition near the surface from the signal of electrons that have scattered elastically but not inelastically. Electrons that have scattered inelastically as well as elastically provide us with information on the possible electronic excitations. Their signal is used to monitor the presence of the Ta2O5 phase near the surface (characterised by a significant band gap of ≃4.5 eV), and estimate at what depth below the surface pure Ta metal is present. In this way, we obtain a fairly detailed picture of the elemental composition and electronic properties of these films.
High Spatial Resolution Thermal Mapping of Volatile Switching in NbOx-Based Memristor Using In Situ Scanning Thermal Microscopy
Publisher: American Chemical Society (ACS)
Date: 14-06-2022
Abstract: Temperature mapping by in situ thermoreflectance thermal imaging (TRTI) or midwave infrared spectroscopy has played an important role in understanding the origins of threshold switching and the effect of insulator-metal transitions in oxide-based memrsitive devices. In this study, we use scanning thermal microscopy (SThM) as an alternative thermal mapping technique that offers high spatial resolution imaging (∼100 nm) and is independent of material. Specifically, SThM is used to map the temperature distribution in NbO
Electric Field- and Current-Induced Electroforming Modes in NbOx
Publisher: American Chemical Society (ACS)
Date: 28-01-2020
Abstract: Electroforming is used to initiate the memristive response in metal/oxide/metal devices by creating a filamentary conduction path in the oxide film. Here, we use a simple photoresist-based detection technique to map the spatial distribution of conductive filaments formed in Nb/NbO
Effect of Electrode Roughness on Electroforming inHfO
Publisher:
American Physical Society (APS)
Date:
29-12-2015
Publisher: American Physical Society (APS)
Date: 29-12-2015
High-endurance megahertz electrical self-oscillation in Ti/NbOx bilayer structures
Publisher: AIP Publishing
Date: 25-05-2015
DOI: 10.1063/1.4921745
Abstract: Electrical self-oscillation is reported for a Ti/NbOx negative differential resistance device incorporated in a simple electric circuit configuration. Measurements confirm stable operation of the oscillator at source voltages as low as 1.06 V, and demonstrate frequency control in the range from 2.5 to 20.5 MHz for voltage changes as small as ∼1 V. Device operation is reported for & .5 × 1010 cycles, during which the operating frequency and peak-to-peak device current decreased by ∼25%. The low operating voltage, large frequency range, and high endurance of these devices makes them particularly interesting for applications such as neuromorphic computing.
Schottky-Barrier-Induced Asymmetry in the Negative-Differential-Resistance Response of
Nb <
Publisher: American Physical Society (APS)
Date: 09-06-2020
Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma
Publisher: IOP Publishing
Date: 16-08-2016
DOI: 10.1088/0029-5515/56/10/104002
Abstract: Helium retention is measured in tungsten s les exposed to mixed H/He plasma in the Magnum-PSI linear plasma device. It is observed that there is very little He retention below helium ion impact energies of 9.0 ± 1.4 eV, indicating the existence of a potential barrier which must be overcome for implantation to occur. The helium retention in s les exposed to plasma at temperatures K is strongly correlated with nano-bubble formation measured using grazing incidence small-angle x-ray scattering. The diameters of nano-bubbles were not found to increase with increasing helium concentration, indicating that additional helium must be accommodated by increasing the bubble concentration or an increase in bubble pressure. For some s les pre-irradiation with heavy ions of 2.0 MeV energy is investigated to simulate the effects of neutron damage. It is observed that nano-bubble sizes are comparable between s les pre-irradiated with heavy-ions, and those without heavy-ion pre-irradiation.
Universal Dynamics Analysis of Locally-Active Memristors and its Applications
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2022
The use of electron Rutherford backscattering to characterize novel electronic materials as illustrated by a case study of sputter-deposited NbO x films
Publisher: Elsevier BV
Date: 12-2014
Low temperature MOCVD of Hg1−xCdxTe on 311, 511, 711 and shaped GaAs
Publisher: Elsevier BV
Date: 1991
The influence of implanted impurities on the thermally-induced epitaxial recrystallization of CoSi2
Publisher: Springer Science and Business Media LLC
Date: 05-1991
Abstract: The influence of implanted impurities (B, O, P, Ar, Xe, Pb, and Bi) on the rate of low-temperature (138 °C), solid-phase epitaxial growth (SPEG) of amorphized CoSi 2 has been studied. SPEG rates of impurity-implanted CoSi 2 , as determined from time-resolved reflectivity measurements, were retarded for all impurities compared to that of Si-implanted CoSi 2 . The extent of retardation varied from a factor of 1.5 for P to 9.4 for Xe. Channeling measurements of impurity-implanted CoSi 2 indicated that Xe and Bi atoms were located on nonsubstitutional lattice sites while ∼40% of Pb atoms occupied either substitutional sites or vacant interstitial cation sites following annealing. The presence of impurities did not affect the CoSi 2 post-anneal crystalline quality, and no significant impurity diffusion was apparent at 138 °C from secondary-ion mass spectrometry measurements.
Nanoindentation of Si Nanocrystals in SiO_2
Publisher: IEEE
Date: 2005
Strong paramagnetism and possible ferromagnetism in pure carbon nanofoam produced by laser ablation
Publisher: Elsevier BV
Date: 04-2005
The structure and electronic properties of tetrahedrally bonded hydrogenated amorphous carbon
Publisher: AIP Publishing
Date: 05-2023
DOI: 10.1063/5.0147494
Abstract: We have synthesized hydrogenated and deuterated amorphous carbon materials that have a density, 2.7 ± 0.1 g/cm3, consistent with almost entirely tetrahedral bonding. In hydrogen-free tetrahedral amorphous carbon, the presence of a minority of sp2 bonded atoms leads to localized states that could be passivated with hydrogen by analogy with hydrogenated amorphous silicon. Neutron diffraction analysis demonstrated that the local bonding environment is consistent with ab initio models of high density hydrogenated tetrahedral amorphous carbon and with the related tetrahedral molecular structure neopentane. The optical bandgap of our material, 4.5 eV, is close to the bandgap in the density of states determined by scanning tunneling spectroscopy (4.3 eV). This bandgap is considerably larger than that of hydrogen-free tetrahedral amorphous carbon, confirming that passivation of sp2 associated tail-states has occurred. Both the structural and electronic measurements are consistent with a model in which the tetrahedrally bonded carbon regions are terminated by hydrogen, causing hopping conductivity to dominate.
Electronic and magnetic properties of carbon nanofoam produced by high-repetition-rate laser ablation
Publisher: Elsevier BV
Date: 09-2002
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