A5005499784- Semiconductor materials and devices
- Photocathodes and Microchannel Plates
- Electronic and Structural Properties of Oxides
- Semiconductor materials and interfaces
- Advancements in Semiconductor Devices and Circuit Design
- Dark Matter and Cosmic Phenomena
- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Integrated Circuits and Semiconductor Failure Analysis
- Ferroelectric and Negative Capacitance Devices
- Ga2O3 and related materials
- Radiation Detection and Scintillator Technologies
- GaN-based semiconductor devices and materials
- Photonic and Optical Devices
- Advanced X-ray Imaging Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Optical Sensing Technologies
- Plasma Diagnostics and Applications
- Maternal Mental Health During Pregnancy and Postpartum
- High-pressure geophysics and materials
- Advanced X-ray and CT Imaging
- Mesoporous Materials and Catalysis
- Crystallography and Radiation Phenomena
- Copper Interconnects and Reliability
University College Cork
2008-2023
Oxford Instruments (United Kingdom)
2016-2021
Eindhoven University of Technology
2021
University of Glasgow
2021
Incom (United States)
2013-2017
INC Research (United Kingdom)
2016
Broadcom (Israel)
2013
Tyndall National Institute
2007-2011
Tyndall Centre
2008-2010
KU Leuven
2009
Electrical properties of metal-oxide-semiconductor capacitors using atomic layer deposited HfO2 on n-type GaAs or InxGa1−xAs (x=0.53, 0.30, 0.15) epitaxial layers were investigated. Capacitance-voltage (CV) measurements indicated large temperature and frequency dispersion at positive gate bias in devices low In content (x=0.30, layers, which is significantly reduced for In0.53Ga0.47As. For In0.53Ga0.47As devices, the CV response negative most likely characteristic an interface state may not...
High mobility III-V substrates with high-k oxides are required for device scaling without loss of channel mobility. Interest has focused on the self-cleaning effect selected during atomic layer deposition Al2O3. A thin (∼1 nm) Al2O3 interface control is deposited In0.53Ga0.47As prior to HfO2 growth, providing benefit and improving quality by reducing state defect densities ∼50% while maintaining trends. Significant reductions in leakage current density increased breakdown voltage found,...
Microchannel plate (MCP) imaging detectors are widely used in astronomical, biological and remote sensing applications. Photon counting mode imagers with event timing can make use of the high spatial resolution (~10- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50~\mu \text {m}$ </tex-math></inline-formula> ) very time (subnanoseconds) MCP to enhance performance such dynamic environments (for example...
The technique of atomic layer deposition (ALD) has enabled the development alternative glass microchannel plates (MCPs) with independently tunable resistive and emissive layers, resulting in excellent thickness uniformity across large area (20 × 20 cm), high aspect ratio (60:1 L/d) substrates. Furthermore, use ALD to deposit functional layers allows optimal substrate material be selected, such as borosilicate glass, which many benefits compared lead-oxide used conventional MCPs, including...
The atomic layer deposition of high dielectric constant oxides like HfO2 on III-V substrates such as In0.53Ga0.47As leads to a poor interface, with the growth native regardless surface pretreatment and passivation method. presence gate leakage current characteristics due low band gap potential wells at interface. In addition, quality this interface very large state defect densities, which are detrimental metal-oxide-semiconductor-based device performance. A wide interlayer replacing oxide...
Band alignment at the interfaces of (100)GaAs with Al2O3 and HfO2 grown using atomic layer deposition is determined internal photoemission photoconductivity measurements. Though inferred conduction valence band offsets for both insulators were found to be close or larger than 2 eV, interlayer by concomitant oxidation GaAs reduces barrier electrons approximately 1 eV. The latter may pose significant problems associated electron injection from into oxide.
We describe the synthesis, characterization, and application of nanocomposite, tunable resistance coatings consisting conducting, metallic nanoparticles embedded in an amorphous dielectric matrix. These films are comprised M:Al 2 O 3 with M=Mo or W, prepared by atomic layer deposition (ALD) using alternating exposures to trimethyl aluminum H for Al ALD MF 6 /Si metal ALD. By varying ratio cycles components film, we can tune precisely these over a very broad range from 10 5 -10 12 Ohm.cm....
Borosilicate microcapillary arrays have been functionalized by Atomic Layer Deposition (ALD) of resistive and secondary emissive layers to produce robust microchannel plates (MCPs) with improved performance characteristics over traditional MCPs. These techniques MCP's enhanced stability lifetime, low background rates, levels adsorbed gas. Using ALD functionalize the substrate decouples two provides opportunity explore many new materials. The borosilicate substrates advantages lead glass...
Abstract Microchannel plates (MCPs) have been used for many years in space flight instrumentation as fast, lightweight electron multipliers. A new MCP fabrication method combines a glass substrate composed of hollow capillary arrays with thin film coatings to provide the resistive and secondary emissive properties. Using this technique, gain, resistance, properties may be chosen independently. Large‐area MCPs are available at moderate cost. Secondary emission films Al 2 O 3 MgO sustained...
The electron energy band alignment at interfaces of InxGa1−xAs (0≤x≤0.53) with atomic-layer deposited insulators Al2O3 and HfO2 is characterized using internal photoemission photoconductivity experiments. the valence top found to be only marginally influenced by semiconductor composition. This result suggests that known bandgap narrowing from 1.42 0.75 eV when In content increases 0 0.53 occurs mostly through downshift conduction bottom. It finds support both hole data. Similarly GaAs case,...
Aims: Maternal mental illness has a significant influence on negative maternal and childhood outcomes. Few studies have focused both depression anxiety, or explored the interplay of mother–infant bond. We aimed to examine relationship between early postnatal attachment at 4 18 months postpartum. Methods: This was secondary analysis 168 mothers recruited from BabySmart Study. All women delivered healthy term infants. Depression anxiety symptoms were measured via Edinburgh Postnatal Scale...
In this work results are presented of an investigation into the structural and electrical properties HfO2 films on GaAs InxGa1-xAs substrates for x: 0.15, 0.30, 0.53. The capacitancevoltage responses (x: 0.15 0.30) dominated by interface defect response. Analysis these samples at 77K indicates that density is > 2.5x1013 cm-2. For HfO2/In0.53Ga0.47As system, capacitance-voltage indicate surface accumulation achieved. consistent with a high density, energy level {greater than or equal...
Abstract The deposition of dielectric materials on graphene is one the bottlenecks for unlocking potential in electronic applications. plasma enhanced atomic layer 10 nm thin high quality aluminum oxide (Al 2 O 3 ) demonstrated using a monolayer hexagonal boron nitride (hBN) as protection layer. Raman spectroscopy performed to analyze possible structural changes lattice caused by deposition. results show that hBN combination with an optimized process can effectively protect from damage,...
Abstract We describe the formation of RuO 2 thin films grown using atomic layer deposition (ALD) on (100) Si substrates from Ru(EtCp) and O , subsequent influence annealing temperature atmosphere surface morphology structure deposited layers. The are characterized scanning electron microscopy (SEM), force (AFM), X‐ray diffraction (XRD), transmission (TEM), (ED). as‐deposited consist islands. No significant changes in composition or observed following N for 4 h at either 500 700°C. Higher...
The quality of the high-k/InxGa1-xAs interface is a crucial factor in achieving high electron mobility compound semiconductor field effect transistors. Capacitance and conductance characterisation methods were employed to evaluate different high-k/InGaAs interfaces. This paper will first discuss specificity capacitance voltage characteristics MOS structures, then recent progress study k/InxGa1 xAs interfaces be presented. measurements are combined provide picture state density. We have also...
Very large (20 cm × 20 cm) flat panel phototubes are being developed which employ novel microchannel plates (MCPs). The MCPs manufactured using borosilicate microcapillary arrays functionalized by the application of resistive and secondary emissive layers atomic layer deposition (ALD). This allows operational parameters to be set tailoring sequential ALD processes. substrates robust, including ability produced in formats square). have performance characteristics (gain, pulse amplitude...
High-quality dielectric films could enable GaN normally off high-electron-mobility transistors (HEMTs). Plasma atomic layer deposition (ALD) is known to allow for controlled high-quality thin-film deposition, and in order not exceed energy flux levels leading device damage, the plasma used should preferably be remote many applications. This article outlines ion distribution functions a new ALD system, Oxford Instruments Atomfab™, which includes an innovative, RF-driven, source. The source...
Control of the high-k/III-V interface by deposition thin (~1-2 nm) control layers (ICLs) Al 2 O 3 or MgO, as part an overall bi-layer structure with a high-k metal oxide MO2 (M = Hf|Zr), is explored. An MgO ICL deposited on unpassivated InxGa1-xAs (x 0|0.53) substrates prior to gate deposition, forming Pd/high-k/ICL/III-V stack. The aim enable continued device scaling using while improving quality and interfacial band structure, ICL. Metal-oxide-semiconductor capacitor (MOSCAP) devices...
In this work we present the results of a combined experimental and theoretical investigation into capacitance-voltage characteristics high-k/In0.53Ga0.47As/InP system. The emphasis is placed on maximum measured capacitance for n p doped In0.53Ga0.47As epitaxial layers. Theoretical calculations based ideal systems indicate highly asymmetric CV response, with an equivalent oxide thickness correction ~ 1.4nm (Γ valley only) 0.23nm high-k/n-In0.53Ga0.47As/InP high-k/p-In0.53Ga0.47As/InP...
This work focuses on the development of novel nano-engineered microchannel plates (MCPs) to enhance a new generation NUV-visible light photon counting detectors that have wide range applications in LIDAR, 3D topographic imaging, high-speed photography, bio-medial fluorescence microscopy and astronomical imaging. The MCPs are borosilicate glass micro-capillary arrays functionalized using atomic layer deposition (ALD). MCP's manufactured this way many advantageous properties, including ability...