A5072839234- Semiconductor Quantum Structures and Devices
- Gold and Silver Nanoparticles Synthesis and Applications
- Plasmonic and Surface Plasmon Research
- Quantum Dots Synthesis And Properties
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Electron and X-Ray Spectroscopy Techniques
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Optical Coatings and Gratings
- Advanced Electron Microscopy Techniques and Applications
- Photonic Crystals and Applications
- Ion-surface interactions and analysis
- Copper Interconnects and Reliability
- Electronic and Structural Properties of Oxides
- Molecular Junctions and Nanostructures
- Metal and Thin Film Mechanics
- nanoparticles nucleation surface interactions
- Copper-based nanomaterials and applications
- ZnO doping and properties
- Advanced Semiconductor Detectors and Materials
- Advanced Materials Characterization Techniques
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- Mechanical and Optical Resonators
Technical University of Denmark
2015-2024
Centre d'Études et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement
2021
Centre de Recherche en Mathématiques de la Décision
2021
Danish Geotechnical Society
2020
Center for Nanoscale Science and Technology
2020
Australian National Fabrication Facility
2020
Ørsted (Denmark)
2011-2012
Imperial College London
2008-2010
London Centre for Nanotechnology
2008
Abstract Electron energy-loss spectroscopy can be used for detailed spatial and spectral characterization of optical excitations in metal nanoparticles. In previous electron experiments on silver nanoparticles with radii smaller than 20 nm, only the dipolar surface plasmon resonance was assumed to play a role. Here, applying individual encapsulated silicon nitride, we observe besides usual dipole an additional corresponding higher angular momenta nanoparticle as small 4 nm. We study radius...
We study the surface plasmon (SP) resonance energy of isolated spherical Ag nanoparticles dispersed on a silicon nitride substrate in diameter range 3.5-26 nm with monochromated electron energy-loss spectroscopy. A significant blueshift SP 0.5 eV is measured when particle size decreases from 26 down to 3.5 nm. interpret observed using three models for metallic sphere embedded homogeneous background material: classical Drude model density profile metal, semiclassical corrected an...
Hydrogen sensors are a prerequisite for the implementation of hydrogen economy due to high flammability hydrogen-air mixtures. They comply with increasingly stringent requirements set by stakeholders, such as automotive industry and manufacturers safety systems, where sensor deactivation is severe but widely unaddressed problem. In response, we report intrinsically deactivation-resistant nanoplasmonic enabled rationally designed ternary PdAuCu alloy nanomaterial, which combines identified...
The integration of dissimilar materials in heterostructures has long been a cornerstone modern science-seminal examples are 2D and van der Waals heterostructures. Recently, new methods have developed that enable the realization ultrathin freestanding oxide films approaching limit. Oxides offer degrees freedom, due to strong electronic interactions, especially 3d orbital electrons, which give rise rich exotic phases. Inspired by this progress, platform for assembling thin with different...
The dependence of surface plasmon coupling on the distance between two nanoparticles (dimer) is basis nanometrology tools such as rulers. Application these nanometric rulers requires an accurate description scaling resonance (SPR) wavelength with distance. Here, we have applied electron energy-loss spectroscopy (EELS) and scanning transmission microscopy (STEM) imaging to investigate relationship SPR gold silver nanosphere dimers (radius R) interparticle (d) in range 0.1R < d R. choice EELS...
Abstract Despite tremendous progress in research on self-assembled nanotechnological building blocks, such as macromolecules 1 , nanowires 2 and two-dimensional materials 3 synthetic self-assembly methods that bridge the nanoscopic to macroscopic dimensions remain unscalable inferior biological self-assembly. By contrast, planar semiconductor technology has had an immense technological impact, owing its inherent scalability, yet it seems unable reach atomic enabled by Here, we use surface...
Noble metals are currently the most common building blocks in plasmonics and thus define available range of optical properties. Their alloying provides a viable strategy to engineer new materials with tunable responses. Despite this attractive prospect, link between composition properties many noble metal alloys is still not well understood. Here, electron energy-loss spectroscopy employed systematically study AuAg AuPd nanoparticles varying compositions. The localized surface plasmons, bulk...
A nanochannel liquid cell was used to quantify the electron inelastic mean free path (<italic>λ</italic><sub>IMFP</sub>) in water. The experimental values show large offsets from generally accepted models, and can be determine thickness a cell.
Discontinuous nanostructured aluminum films can support surface-enhanced Raman spectroscopy using excitation in the near infrared range.
The rapidly developing quantum communication technology requires deterministic emitters that can generate single photons and entangled photon pairs in the third telecom window, order to be compatible with existing optical fiber networks on-chip silicon photonic processors. InAs/InP dots (QDs) are among leading candidates for this purpose, due their high emission efficiency required spectral range. However, fabricating versatile QD-based is challenging, especially as these QDs typically have...
Large metal nanostructures with subnanometer interparticle separations (gaps) can provide extremely high local fields and are of particular interest in surface enhanced spectroscopy, as well for basic understanding plasmonics. In this experimental electron energy loss study, we monitor the transition plasmonic dimers from a classical to quantum system by decreasing gaps dimensions when tunneling occurs conductive nanobridge evolves. Our studies show that silver atomic scale exhibit regime,...
Due to their band-structure and optical properties, InAs/InP quantum dots (QDs) constitute a promising system for single-photon generation at the third telecom window of silica fibers applications in communication networks. However, obtaining necessary low in-plane density emitters remains challenge. Such structures are also still less explored than InAs/GaAs counterparts regarding properties confined carriers. Here, we report on growth via metal-organic vapor phase epitaxy investigation...
Electron energy-loss spectroscopy (EELS) has become increasingly popular for detailed characterization of plasmonic nanostructures, owing to the unparalleled spatial resolution this technique. The typical setup in EELS requires nanoparticles be supported on thin substrates. However, as optical measurements, substrate material can modify acquired signal. Here, we have investigated how signal recorded from silver and gold spheroidal at different electron beam impact parameter positions is...
The optical properties of semiconductor quantum dots are greatly influenced by their strain state. Dark field electron holography has been used to measure the in InAs grown InP with a spatial resolution 1 nm. A value 5.4% ± 0.1% determined which is consistent both measurements made geometrical phase analysis high angle annular dark scanning transmission microscopy images and simulations.
The inclusion of silver plasmonic nanoparticles in silicon is highly relevant for photovoltaics as it may enhance optical absorption. We report an investigation the stability such pristine embedded a-Si upon heat treatment. have investigated morphological changes via situ and ex high-resolution high-angle annular dark-field scanning transmission electron microscopy (HRTEM HAADF STEM). melting Ag particles subsequent interdiffusion Si atoms are strongly related to size nanoparticles, well...
We present the expected coating performance based on design and simulations, tested evaluated by means of X-ray reflectometry short long term stability several materials considered as options for mirrors ATHENA mission. As part this study we also report compatibility reflecting coatings to industrial processes involved in assembly mirror modules using Silicon Pore Optics technology.
This work shows how to control the surface density and size of InAs/InP quantum dots over a wide range by tailoring conditions Stranski-Krastanov growth. We demonstrate that in near-critical growth regime, can be tuned between
The dependence of the optical properties InAs/GaAs quantum dot (QD) bilayers on seed layer growth temperature and second InAs coverage is investigated. As increased, a low density large QDs obtained. This results in concomitant increase size layer, which extends their emission wavelength, reaching saturation value around 1400 nm at room for GaAs-capped bilayers. Capping with InGaAs further extension to 1515 narrow linewidth 22 meV. Addition more high does not result significant wavelength as...
The epitaxial growth of InAs/InGaAsP/InP quantum dots (QDs) for emission around 1.5 μm by depositing a thin layer GaAs on top the QDs is presented in this letter. infuence various parameters properties QDs, particular, size, shape, chemical composition, and wavelength are investigated. Continuous wave lasing ridge waveguide QD laser structures range demonstrated.
Emerging applications of self-assembled semiconductor quantum dot (QD)-based nonclassical light sources emitting in the telecom C-band (1530 to 1565 nm) present challenges terms controlled synthesis their low-density ensembles, critical for device processing with an isolated QD. This work shows how control surface density and size InAs/InP dots over a wide range by tailoring conditions Stranski-Krastanow growth. We demonstrate that near-critical growth regime, can be tuned between $10^7$...