A5032184379- Graphene research and applications
- 2D Materials and Applications
- Magnetic and transport properties of perovskites and related materials
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Multiferroics and related materials
- Electronic and Structural Properties of Oxides
- Electron and X-Ray Spectroscopy Techniques
- Nanowire Synthesis and Applications
- Quantum Dots Synthesis And Properties
- Semiconductor materials and devices
- Magnetic properties of thin films
- MXene and MAX Phase Materials
- Plasmonic and Surface Plasmon Research
- Rare-earth and actinide compounds
- Transition Metal Oxide Nanomaterials
- Advancements in Photolithography Techniques
- Ga2O3 and related materials
- Salmonella and Campylobacter epidemiology
- Surface Roughness and Optical Measurements
- Surface and Thin Film Phenomena
- Quantum and Classical Electrodynamics
- Boron and Carbon Nanomaterials Research
- Ocular and Laser Science Research
- Perovskite Materials and Applications
McMaster University
2018-2024
Harvard University
2022-2024
Harvard University Press
2024
Cairo University
2020
The layered square-planar nickelates, Nd$_{n+1}$Ni$_{n}$O$_{2n+2}$, are an appealing system to tune the electronic properties of nickelates via dimensionality; indeed, superconductivity was recently observed in Nd$_{6}$Ni$_{5}$O$_{12}$ thin films. Here, we investigate role epitaxial strain competing requirements for synthesis $n=3$ Ruddlesden-Popper compound, Nd$_{4}$Ni$_{3}$O$_{10}$, and subsequent reduction phase, Nd$_{4}$Ni$_{3}$O$_{8}$. We synthesize our highest quality...
Abstract Reliable, controlled doping of 2D transition metal dichalcogenides will enable the realization next‐generation electronic, logic‐memory, and magnetic devices based on these materials. However, to date, accurate control over dopant concentration scalability process remains a challenge. Here, systematic study scalable in situ fully coalesced WSe 2 films with Re atoms via metal–organic chemical vapor deposition is reported. Dopant concentrations are uniformly distributed substrate...
The rare-earth nickelates possess a diverse set of collective phenomena including metal-to-insulator transitions, magnetic phase and, upon chemical reduction, superconductivity. Here, we demonstrate epitaxial stabilization layered in the Ruddlesden-Popper form, Nd$_{n+1}$Ni$_n$O$_{3n+1}$, using molecular beam epitaxy. By optimizing stoichiometry parent perovskite NdNiO$_3$, can reproducibly synthesize $n = 1 - 5$ member compounds. X-ray absorption spectroscopy at O $K$ and Ni $L$ edges...
Developing novel antimicrobials capable of controlling multidrug-resistant bacterial pathogens is essential to restrict the use antibiotics. Bacteriophages (phages) constitute a major resource that can be harnessed as an alternative traditional antimicrobial therapies. Phage ZCSE2 was isolated among several others from raw sewage but distinguished by broad-spectrum activity against Salmonella serovars considered pathogenic humans and animals. Lytic profiles panel were determined together...
Near-infrared-to-visible second harmonic generation from air-stable two-dimensional polar gallium and indium metals is described. The photonic properties of 2D metals, including the largest second-order susceptibilities reported for (approaching 10 nm/V), are determined by atomic-level structure bonding two-to-three-atom-thick crystalline films. bond character evolved covalent to metallic over a few atomic layers, changing out-of-plane metal–metal distances approximately ten percent (0.2 Å),...
Abstract This work is a systematic experimental and theoretical study of the in‐plane dielectric functions 2D gallium indium films consisting two or three atomic metal layers confined between silicon carbide graphene with corresponding bonding gradient from covalent to metallic van der Waals type. k ‐space resolved free electron bound contributions optical response are identified, latter pointing towards existence thickness dependent quantum confinement phenomena. The resonance energies in...
Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis such could enable the creation materials with tailored, on-demand, electronic optical properties for applications that utilize tunable plasmonic coupling, nonlinearity, epsilon-near-zero behavior, or wavelength-specific light trapping. In this work, it is demonstrated electronic, superconducting, air-stable can be controllably tuned by formation alloys....
A scalable platform to synthesize ultrathin heavy metals may enable high-efficiency charge-to-spin conversion for next-generation spintronics. Here, we report the synthesis of air-stable, epitaxially registered monolayer Pb underneath graphene on SiC (0001) by confinement heteroepitaxy (CHet). Diffraction, spectroscopy, and microscopy reveal that CHet-based intercalation predominantly exhibits a mottled hexagonal superstructure due an ordered network Frenkel-Kontorova-like domain walls. The...
Abstract Novel confinement techniques facilitate the formation of non‐layered 2D materials. Here it is demonstrated that and properties oxides (GaO x , InO SnO ) at epitaxial graphene (EG)/silicon carbide (SiC) interface dependent on EG buffer layer prior to element intercalation. Using Ga, defects in lead Ga transforming GaO with non‐periodic oxygen a crystalline matrix via air oxidation room temperature. However, monolayer 2 bilayer O 3 ferroelectric wurtzite structure(FE‐WZ') can then be...
Scalable synthesis of two-dimensional gallium (2D-Ga) covered by graphene layers was recently realized through confinement heteroepitaxy using silicon carbide substrates. However, the thickness, uniformity, and area coverage 2D-Ga heterostructures have not previously been studied with high-spatial resolution techniques. In this work, we resolve measure heterostructure thicknesses scanning electron microscopy (SEM). Utilizing multiple correlative methods, find that SEM image contrast is...
The oxidation- and air-stability of 2D gallium-intercalated monolayer epitaxial graphene was determined using correlative microscopy. Site-specific studies including AFM, scanning electron microscope, cross section STEM-HAADF, EELS revealed that the oxygen signal detected by XPS AES analyses originated from oxidized surface carbon contaminants without presence at gallium layers. In addition, correlated with intact graphene. absence leads to oxidation in air, consequently losing crystallinity...
A scalable platform to synthesize ultrathin heavy metals may enable high efficiency charge-to-spin conversion for next-generation spintronics. Here we report the synthesis of air-stable, epitaxially registered monolayer Pb underneath bilayer graphene on SiC (0001) by confinement heteroepitaxy (CHet). Diffraction, spectroscopy, and microscopy reveal CHet-based intercalation predominantly exhibits a mottled hexagonal superstructure due an ordered network Frenkel-Kontorova-like domain walls....
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Here the novel direct heteroepitaxial growth method of a 3D system is demonstrated on substrate, CdTe (111)/Al2 O3 (0001), which forms spontaneous vdW-like bond at interface, instead two crystals being strongly bound. Despite large lattice mismatch, thin films are single and maintain high quality due compliance interface accommodates strain. This weak bonding accomplished by self-assembly pseudomorphic chalcogenide layer sapphire surface during growth. Since spontaneously in situ growth, it...
In this work, we present an optimization method for three-dimensional (3D) reconstruction of scanning electron microscope (SEM) images based on angle-of-incidence effects.Therefore, there would be less need to perform further time-consuming tests such as atomic force microscopy (AFM), so analyze the 3D topography.The proposed requires a small number taken after rotating stage.In paper illustrate using eight angles, unlike stereo-photogrammetry methods requiring hundreds [1].At each angle...
An abstract is not available for this content so a preview has been provided. As you have access to content, full PDF via the ‘Save PDF’ action button.
The layered square-planar nickelates, Nd$_{n+1}$Ni$_{n}$O$_{2n+2}$, are an appealing system to tune the electronic properties of nickelates via dimensionality; indeed, superconductivity was recently observed in Nd$_{6}$Ni$_{5}$O$_{12}$ thin films. Here, we investigate role epitaxial strain competing requirements for synthesis $n=3$ Ruddlesden-Popper compound, Nd$_{4}$Ni$_{3}$O$_{10}$, and subsequent reduction phase, Nd$_{4}$Ni$_{3}$O$_{8}$. We synthesize our highest quality...
An abstract is not available for this content so a preview has been provided. As you have access to content, full PDF via the ‘Save PDF’ action button.
Since the discovery of graphene in 2004 [1] there has been a flurry activity investigating two dimensional (2D) materials, because their superlative properties: spin-orbit coupling, massless Dirac fermions, mechanical strength, thermal and chemical stability [2] . Remarkably, in-plane hexagonal symmetry is largely responsible for its behavior. However, zero-band gap presents hurdles to use as semiconductor. This spurred interest synthesis other van der Waals 2D structures, such h-BN [3] more...
Introduction:Arc welders are at high risk for developing phototoxic maculopathy, as diagnosed by using Optical Coherence Tomography (OCT), which describes some structural changes in the fovea of with disruption inner reflective layer corresponding to outer neurosensory retina.Aim work: To evaluate use (OCT) a method monitoring workers involved arc welding early detection any retinal damage.Materials and methods: The study included 66 exposed an automobile factory Helwan, Cairo.A matched...