A5091349221- Surface Chemistry and Catalysis
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Advanced Memory and Neural Computing
- Force Microscopy Techniques and Applications
- Carbon Nanotubes in Composites
- Surface and Thin Film Phenomena
- Graphene research and applications
- Electronic and Structural Properties of Oxides
- Silicon Nanostructures and Photoluminescence
- Machine Learning in Materials Science
- Ionic liquids properties and applications
- Polymer Nanocomposites and Properties
- Transition Metal Oxide Nanomaterials
- Advanced Materials and Mechanics
- Catalytic Processes in Materials Science
- Cancer Research and Treatments
- Mechanical and Optical Resonators
- nanoparticles nucleation surface interactions
- Thin-Film Transistor Technologies
- Block Copolymer Self-Assembly
- Ferroelectric and Negative Capacitance Devices
- Silicon and Solar Cell Technologies
- Various Chemistry Research Topics
- Covalent Organic Framework Applications
Nanolayers
2018-2023
University College London
2012-2022
Norwegian University of Science and Technology
2019-2022
Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
2019
Pennsylvania State University
2017-2018
UK Astronomy Technology Centre
2018
Tohoku University
2014-2017
University of Modena and Reggio Emilia
2017
London Centre for Nanotechnology
2016-2017
PerkinElmer (United States)
2012
DScribe is a software package for machine learning that provides popular feature transformations ("descriptors") atomistic materials simulations. accelerates the application of property prediction by providing user-friendly, off-the-shelf descriptor implementations. The currently contains implementations Coulomb matrix, Ewald sum sine Many-body Tensor Representation (MBTR), Atom-centered Symmetry Function (ACSF) and Smooth Overlap Atomic Positions (SOAP). Usage illustrated two different...
Despite extensive experimental and theoretical studies, the atomistic mechanisms responsible for dielectric breakdown (BD) in amorphous (a)-SiO2 are still poorly understood. A number of qualitative physical models mathematical formulations have been proposed over years to explain experimentally observable statistical trends. However, these do not provide clear insight into origins BD process. Here, we investigate a-SiO2 using a multi-scale approach where energetic parameters derived from...
On-surface synthesis with molecular precursors has emerged as the de facto route to atomically well-defined graphene nanoribbons (GNRs) controlled zigzag and armchair edges. On Au(111) Ag(111) surfaces, prototypical precursor 10,10′-dibromo-9,9′-bianthryl (DBBA) polymerizes through an Ullmann reaction form straight GNRs However, on Cu(111), irrespective of bianthryl (dibromo-, dichloro-, or halogen-free bianthryl), is inactive, instead, identical chiral are formed. Using resolved noncontact...
We review the current understanding of intrinsic electron and hole trapping in insulating amorphous oxide films on semiconductor metal substrates. The experimental theoretical evidences are provided for existence deep trap states stemming from disorder networks. start presenting results (a) HfO2, chosen due to availability highest purity films, which is vital studying their electronic properties. Exhaustive photo-depopulation spectroscopy measurements calculations using density functional...
Using density functional theory (DFT) calculations, we investigated oxygen vacancy diffusion and aggregation in relation to dielectric breakdown amorphous silicon dioxide (a-SiO2). Our calculations indicate the existence of favourable sites for formation dimers trimers network with maximum binding energies approximately 0.13 eV 0.18 eV, respectively. However, an average energy barrier height neutral is found be about 4.6 rendering this process unfeasible. At Fermi level positions above 6.4...
Dielectric oxide films in electronic devices undergo significant structural changes during device operation under bias. These are usually attributed to aggregation of oxygen vacancies resulting formation depleted regions and conductive filaments. However, neutral have high diffusion barriers ionic oxides their interaction propensity for still poorly understood. In this paper we briefly review the existing data on static configurations dimers trimers technologically relevant SiO$_2$ HfO$_2$...
Electrically biasing thin films of amorphous, substoichiometric silicon oxide drives surprisingly large structural changes, apparent as density variations, oxygen movement, and ultimately, emission superoxide ions. Results from this fundamental study are directly relevant to materials that increasingly used in a range technologies, demonstrate surprising level field-driven local reordering random network.
Using density functional theory (DFT) calculations we demonstrate how electron injection can facilitate the creation of Frenkel defects in amorphous (a)-SiO2. The precursor sites composed wide O-Si-O bond angles SiO2 act as deep traps and accommodate up to two extra electrons. Trapping electrons at these intrinsic results weakening a Si-O creates an efficient breaking pathway for producing neutral O vacancies [Formula: see text] interstitial ions characterized by low transition barriers....
Layered oxides exhibit high ionic mobility and chemical flexibility, attracting interest as cathode materials for lithium-ion batteries the pairing of hydrogen production carbon capture. Recently, layered emerged highly tunable semiconductors. For example, by introducing anti-Frenkel defects, electronic hopping conductance in hexagonal manganites was increased locally orders magnitude. Here, we demonstrate local acceptor donor doping Er(Mn,Ti)O$_3$, facilitated splitting such defects under...
We demonstrate that using metallic tips for noncontact atomic force microscopy (NC-AFM) imaging at relatively large (>0.5 nm) tip-surface separations provides a reliable method studying molecules on insulating surfaces with chemical resolution and greatly reduces the complexity of interpreting experimental data. The NC-AFM theoretical simulations were carried out NiO(001) surface as well adsorbed CO Co-Salen Cr-coated Si tips. results density functional theory calculations confirm possess...
Although it is recognized that the dynamic behavior of adsorbing molecules strongly affects entropic contribution to adsorption free energy, detailed studies entropy large organic at insulating surfaces are still rare. We compared two different functionalized molecules, 1,3,5-tri(4-cyano-4,4-biphenyl)benzene (TCB) and 1,4-bis(cyanophenyl)-2,5-bis(decyloxy)benzene (CDB), on KCl(001) surface using density functional theory (DFT) molecular dynamics (MD) simulations. The accuracy van der Waals...
The importance and mechanisms of transient mobility atoms molecules adsorbing at surfaces have been a subject controversy for many years. We used classical molecular dynamics simulations to examine Pd on the MgO (100) surface with incident kinetic energies not exceeding 0.4 eV. calculations show that deposited exhibit high temperatures below 80 K where contribution from thermal diffusion processes should be negligible. For our selected deposition conditions, aimed simulation cluster growth...
Achieving control over formation of molecular films on insulating substrates is important for designing novel 2D functional materials and devices. To study the main factors governing successful control, organic molecules with interchangeable polar groups, a variable length aromatic body, flexible hydrocarbon chains are designed, synthesized then deposited (001) surfaces bulk sodium chloride, potassium rubidium chloride. The structures imaged using noncontact atomic force microscopy modeled...
Individual molecules of Co-Salen, a small chiral paramagnetic metal–organic complex, deposited on NiO(001) were imaged with noncontact atomic force microscopy (NC-AFM) using metallic Cr coated tips. Experimentally, we simultaneously resolve both the molecule and individual surface ions. Images recorded at low temperatures show that Co-Salen are aligned slightly away from ⟨110⟩ directions Co center is located above bright spot in atomically resolved images surface. Density functional theory...
We studied the effect of molecular flexibility on morphology and growth mechanisms self-assembled films an insulating substrate using a combination experimental theoretical methods. 1,3,5-Tri-(4-cyano-4,4 biphenyl)-benzene (TCB) 1,4-bis(cyanophenyl)-2,5-bis(decyloxy) benzene (CDB) molecules were deposited KCl (001) surface imaged noncontact atomic force microscopy (NC-AFM). Both designed to contain same anchoring groups ring structures, yet CDB structures observed grow from step edges, while...
We apply a three-dimensional (3D) physical simulator, coupling self-consistently stochastic kinetic Monte Carlo descriptions of ion and electron transport, to investigate switching in silicon-rich silica (SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) redox-based resistive random-access memory (RRAM) devices. explain the intrinsic nature resistance SiO layer, demonstrate impact self-heating effects initial vacancy distributions on...
The renin-angiotensin system (RAS) is well studied for its regulation of blood pressure and fluid homeostasis, as increased activity associated with a variety diseases conditions, including cardiovascular disease, diabetes, kidney disease. enzyme renin cleaves angiotensinogen to form angiotensin I (ANG I), which further cleaved by angiotensin-converting produce ANG II. Although II the main effector molecule RAS, rate-limiting enzyme, thus playing pivotal role in regulating RAS hypertension...
Electrically biasing thin films of amorphous, substoichiometric silicon oxide drives surprisingly large structural changes, apparent as density variations, oxygen movement, and, ultimately, emission superoxide ions. The results from the fundamental study by A. Mehonic, J. Kenyon, and co-workers reported on page 7486 are directly relevant to materials that increasingly used in a range technologies, demonstrate surprising level field-driven local reordering random network.
We present an efficient scheme for parametrizing complex molecule-surface force fields from ab initio data. The cost of producing a sufficient fitting library is mitigated using 2D periodic embedded slab model made possible by the quantum mechanics/molecular mechanics in CP2K. These results were then used conjunction with genetic algorithm (GA) methods to optimize large parameter sets needed describe such systems. derived potentials are able well reproduce adsorption geometries and energies...
Three-dimensional atomic force microscopy (3D-AFM) has resolved three-dimensional distributions of solvent molecules at solid–liquid interfaces the subnanometer scale. This method is now being extended to imaging biopolymer assemblies such as chromosomes or proteins in cells, with expectation able resolve their structures. Here, we have developed a computational simulate 3D-AFM images biopolymers by using Jarzynski equality. It found that some parts fiber structure are indeed image. The...