David Walker
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View article: Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection
Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection Open
Hafnium oxide (HfO x ) films grown by atomic layer deposition (ALD) have recently been demonstrated to provide high‐quality silicon surface passivation. Reports have suggested that changing the composition of the hafnium‐containing precurs…
View article: Temperature-Dependent Structural and Optoelectronic Properties of the Layered Perovskite 2-Thiophenemethylammonium Lead Iodide
Temperature-Dependent Structural and Optoelectronic Properties of the Layered Perovskite 2-Thiophenemethylammonium Lead Iodide Open
Improved knowledge of the influence of temperature upon layered perovskites is essential to enable perovskite-based devices to operate over a broad temperature range and to elucidate the impact of structural changes upon the optoelectronic…
View article: Flexoelectric polarizing and control of a ferromagnetic metal
Flexoelectric polarizing and control of a ferromagnetic metal Open
Electric polarization is well defined only in insulators not metals, and there is no general scheme to induce and control bulk polarity in metals. Here we circumvent this limitation by utilizing a pseudo-electric field generated by inhomog…
View article: Mechanisms of inclusion of thallium-201 into Prussian blue nanoparticles for nuclear medicine applications
Mechanisms of inclusion of thallium-201 into Prussian blue nanoparticles for nuclear medicine applications Open
Prussian blue nanoparticles are radiolabelled with Tl-201 and characterised to provide the unambiguous confirmation of the inclusion mechanism.
View article: Flexoelectric polarizing and control of a ferromagnetic metal
Flexoelectric polarizing and control of a ferromagnetic metal Open
Data for Figures 1, 3, 4, and 5
View article: Untangling free carrier and exciton dynamics in layered hybrid perovskites using ultrafast optical and terahertz spectroscopy
Untangling free carrier and exciton dynamics in layered hybrid perovskites using ultrafast optical and terahertz spectroscopy Open
Layered hybrid perovskites (LPKs) are promising as alternatives or additives to 3D metal halide perovskites for optoelectronic applications including photovoltaic cells, LEDs and lasers due to their increased stability. However, high excit…
View article: Passivating Polycrystalline Copper with an Ultrathin Samarium Layer
Passivating Polycrystalline Copper with an Ultrathin Samarium Layer Open
Herein, it is reported that how a layer of samarium (Sm) with a thickness equivalent to ≈2 atoms (0.8 nm) deposited by thermal evaporation is remarkably effective at passivating polycrystalline copper (Cu) toward oxidation in ambient air. …
View article: Quantifying Electrochemical Degradation in Single-crystalline LiNi0.8Mn0.1Co0.1O2–Graphite pouch cells through Operando X-ray and Post-mortem Investigations
Quantifying Electrochemical Degradation in Single-crystalline LiNi0.8Mn0.1Co0.1O2–Graphite pouch cells through Operando X-ray and Post-mortem Investigations Open
Layered nickel-rich lithium transition metal oxides (LiNixMnyCo1−x−yO2; where x ≥ 0.8), with single-crystalline morphology, are promising future high-energy-density Li-ion battery cathodes due to their ability to mitigate particle-cracking…
View article: Influence of co-reactants on surface passivation by nanoscale hafnium oxide layers grown by atomic layer deposition on silicon
Influence of co-reactants on surface passivation by nanoscale hafnium oxide layers grown by atomic layer deposition on silicon Open
Hafnium oxide thin films have attracted considerable interest for passivation layers, protective barriers, and anti-reflection coatings. This study presents a systematic investigation into the role of film growth co-reactant on film proper…
View article: Activation of Al2O3 surface passivation of silicon: Separating bulk and surface effects
Activation of Al2O3 surface passivation of silicon: Separating bulk and surface effects Open
Understanding surface passivation arising from aluminium oxide (Al2O3) films is of significant relevance for silicon-based solar cells and devices that require negligible surface recombination. This study aims to understand the competing b…
View article: Terahertz Emission via Optical Rectification in a Metal-Free Perovskite Crystal
Terahertz Emission via Optical Rectification in a Metal-Free Perovskite Crystal Open
We report on the emission of high-intensity pulsed terahertz radiation from the metal-free halide perovskite single crystal methyl-DABCO ammonium iodide (MDNI) under femtosecond illumination. The power and angular dependence of the THz out…
View article: Algorithms for Encoding and Decoding 3D Hilbert Orderings
Algorithms for Encoding and Decoding 3D Hilbert Orderings Open
This paper presents algorithms and pseudocode for encoding and decoding 3D Hilbert orderings.
View article: Operando X-ray and Post-mortem Investigations of Electrochemical Degradation in Single-crystalline LiNi0.8Mn0.1Co0.1O2–Graphite pouch cells
Operando X-ray and Post-mortem Investigations of Electrochemical Degradation in Single-crystalline LiNi0.8Mn0.1Co0.1O2–Graphite pouch cells Open
Layered nickel-rich lithium transition metal oxides (LiNixMnyCo1−x−yO2; where x ≥ 0.8), with single-crystalline morphology, are promising future high-energy-density Li-ion battery cathodes due to their ability to mitigate particle-cracking…
View article: Highly Air Stable Tin Halide Perovskite Photovoltaics using a Bismuth Capped Copper Top Electrode
Highly Air Stable Tin Halide Perovskite Photovoltaics using a Bismuth Capped Copper Top Electrode Open
An effective approach is reported to enhance the stability of inverted organo‐tin halide perovskite photovoltaics based on capping the cathode with a thin layer of bismuth. Using this simple approach, unencapsulated devices retain up to 70…
View article: Hafnium oxide: A thin film dielectric with controllable etch resistance for semiconductor device fabrication
Hafnium oxide: A thin film dielectric with controllable etch resistance for semiconductor device fabrication Open
Thin film dielectrics are ubiquitous in the manufacture of electronic devices and are frequently deposited and etched away at various stages of device fabrication. We demonstrate that hafnium oxide (HfO2) thin films grown via atomic layer …
View article: Understanding dehydration of Prussian white: from material to aqueous processed composite electrodes for sodium-ion battery application
Understanding dehydration of Prussian white: from material to aqueous processed composite electrodes for sodium-ion battery application Open
Understanding dehydration of Prussian white systems to enable processability of water-based electrodes for sustainable and high capacity sodium-ion batteries.
View article: Mechanisms of Silicon Surface Passivation by Negatively Charged Hafnium Oxide Thin Films
Mechanisms of Silicon Surface Passivation by Negatively Charged Hafnium Oxide Thin Films Open
We have studied the mechanisms underpinning effective surface passivation of silicon with hafnium oxide (HfO 2 ) thin films grown via atomic layer deposition (ALD). Plasma-enhanced ALD with O 2 plasma and a tetrakis(dimethylamido)hafnium p…
View article: Atomic-scale investigation of the reversible α- to ω-phase lithium ion charge – discharge characteristics of electrodeposited vanadium pentoxide nanobelts
Atomic-scale investigation of the reversible α- to ω-phase lithium ion charge – discharge characteristics of electrodeposited vanadium pentoxide nanobelts Open
Electrodeposition is used to produce α-V 2 O 5 nanobelts on a boron doped diamond electrode. The nanoscale dimensions facilitate accommodation of three Li + ions during discharge resulting in ω-Li 3 V 2 O 5 , which is reversible over at le…
View article: A powder XRD, solid state NMR and calorimetric study of the phase evolution in mechanochemically synthesized dual cation (Cs<sub><i>x</i></sub>(CH<sub>3</sub>NH<sub>3</sub>)<sub>1−<i>x</i></sub>)PbX<sub>3</sub> lead halide perovskite systems
A powder XRD, solid state NMR and calorimetric study of the phase evolution in mechanochemically synthesized dual cation (Cs<sub><i>x</i></sub>(CH<sub>3</sub>NH<sub>3</sub>)<sub>1−<i>x</i></sub>)PbX<sub>3</sub> lead halide perovskite systems Open
Mechanochemically synthesized dual cation hybrid perovskites of the form (Cs x MA 1− x )Pb(Cl/Br) 3 ( x = 0–1) exhibit complete miscibility and high structural order across each compositional range.
View article: Atomic-Scale Investigation of the Reversible alpha to omega-Phase Lithium Ion Charge – Discharge Characteristics of Electrodeposited Vanadium Pentoxide Nanobelts
Atomic-Scale Investigation of the Reversible alpha to omega-Phase Lithium Ion Charge – Discharge Characteristics of Electrodeposited Vanadium Pentoxide Nanobelts Open
Using an electrochemical potential pulse methodology in a mixed solvent system, electrochemical deposition of amorphous vanadium pentoxide (V2O5) nanobelts is possible. Crystallisation of the material is achieved using in air annealing wit…
View article: Non-ambient X-ray and neutron diffraction of novel relaxor ferroelectric<i>x</i>Bi<sub>2</sub>(Zn<sub>2/3</sub>,Nb<sub>1/3</sub>)O<sub>3</sub>–(1 –<i>x</i>)BaTiO<sub>3</sub>
Non-ambient X-ray and neutron diffraction of novel relaxor ferroelectric<i>x</i>Bi<sub>2</sub>(Zn<sub>2/3</sub>,Nb<sub>1/3</sub>)O<sub>3</sub>–(1 –<i>x</i>)BaTiO<sub>3</sub> Open
The first determination of the phase diagram of the novel ferroelectric relaxor x Bi(Zn 2/3 Nb 1/3 )O 3 –(1 − x )BaTiO 3 (BZN-BT) has been achieved with a combination of high-resolution X-ray and neutron diffraction up to the miscibility l…
View article: Controlling Magnetic Anisotropy in a Zero-Dimensional <i>S</i> = 1 Magnet Using Isotropic Cation Substitution
Controlling Magnetic Anisotropy in a Zero-Dimensional <i>S</i> = 1 Magnet Using Isotropic Cation Substitution Open
The [Zn1-xNix(HF2)(pyz)2]SbF6 (x = 0.2; pyz = pyrazine) solid solution exhibits a zero-field splitting (D) that is 22% larger [D = 16.2(2) K (11.3(2) cm-1)] than that observed in the x = 1 material [D = 13.3(1) K (9.2(1) cm-1)]. The substa…
View article: Bismuth zinc niobate: BZN-BT, a new lead-free BaTiO<sub>3</sub>-based ferroelectric relaxor?
Bismuth zinc niobate: BZN-BT, a new lead-free BaTiO<sub>3</sub>-based ferroelectric relaxor? Open
The novel lead-free ferroelectric relaxor system [Formula: see text](Bi([Formula: see text] [Formula: see text][Formula: see text](1[Formula: see text]BaTiO 3 ([Formula: see text]BZN(1[Formula: see text]BT) has received interest as a high-…
View article: CCDC 1952142: Experimental Crystal Structure Determination
CCDC 1952142: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: An improved and readily available version of <i>Bst</i> DNA Polymerase for LAMP, and applications to COVID-19 diagnostics
An improved and readily available version of <i>Bst</i> DNA Polymerase for LAMP, and applications to COVID-19 diagnostics Open
Despite the fact that strand-displacing activity is of great utility for a variety of applications, including isothermal amplification assays, there are relatively few strand-displacing DNA polymerases. In particular, the thermotolerant DN…