A5029412889- Photonic Crystals and Applications
- Quasicrystal Structures and Properties
- Advanced Memory and Neural Computing
- Metamaterials and Metasurfaces Applications
- X-ray Diffraction in Crystallography
- Photonic and Optical Devices
- Neuroscience and Neural Engineering
- Plasmonic and Surface Plasmon Research
- Ferroelectric and Negative Capacitance Devices
- Ion-surface interactions and analysis
- Mineralogy and Gemology Studies
- Aluminum Alloy Microstructure Properties
- Organic and Molecular Conductors Research
- stochastic dynamics and bifurcation
- Anodic Oxide Films and Nanostructures
- Electron and X-Ray Spectroscopy Techniques
- Analytical Chemistry and Sensors
- Transition Metal Oxide Nanomaterials
- Silicon Nanostructures and Photoluminescence
- Phase-change materials and chalcogenides
- Photocathodes and Microchannel Plates
- Semiconductor materials and devices
- Environmental and Agricultural Sciences
- Integrated Circuits and Semiconductor Failure Analysis
- Nanoporous metals and alloys
University of Cambridge
2024
Laboratoire de physique des Solides
2008-2023
Centre National de la Recherche Scientifique
2004-2023
Université Paris-Saclay
1995-2023
Université Paris-Sud
2000-2019
Tianjin Geothermal Exploration, Development and Design Institute (China)
2004
Université Paris Cité
1988-2000
We report on the fabrication of three-dimensional (3D) Yablonovite-like photonic crystals by focused-ion-beam (FIB) etching macroporous silicon. Crystals containing up to 25×25×5 lattice cells are fabricated with a submicronic period ∼0.75 μm. Photonic band gaps at wavelengths close 3 μm demonstrated from reflection measurements and confirmed numerical calculations. The combination plasma or chemical FIB micromachining appears be promising for large variety multiple-period 3D optical wavelengths.
The phenomenon of resistive switching (RS), which was initially linked to non-volatile memory applications, has recently also been associated with the concept memristors, whose adjustable multilevel resistance characteristics open up unforeseen perspectives in cognitive computing. Herein, we demonstrate that states LixCoO2 thin film-based metal-insulator-metal (MIM) solid-state cells can be tuned by sequential programming voltage pulses and these are dramatically dependent on input rate,...
Abstract We introduce a voltage-gated conductance model for an artificial neuron that exhibits tonic, fast, and two types of intrinsic burst spiking. The spike generation is achieved with single channel exploits the commutation properties two-terminal memristive device. Our circuit implementation unprecedented simplicity, using just four electronic components, all conventional, cheap out-of-the-shelf. bursting two-compartment model, similar to Pinsky–Rinzel model. obtain full phase diagram...
Abstract Lithium cobalt oxide nanobatteries offer exciting prospects in the field of nonvolatile memories and neuromorphic circuits. However, precise underlying resistive switching (RS) mechanism remains a matter debate two‐terminal cells. Herein, intriguing results, obtained by secondary ion mass spectroscopy (SIMS) 3D imaging, clearly demonstrate that RS corresponds to lithium migration toward outside Li x CoO 2 layer. These observations are very well correlated with observed...
We demonstrate that extremely high aspect ratio patterns can be created at a submicrometre scale using focused-ion-beam etching in porous material. Thanks to preliminary microscopic structuration of the material, limiting effects usually observed bulk material ion-beam are strongly reduced. Holes with an overall 50 obtained. In combination photo-electrochemical etching, this method is successfully used fabricate three-dimensional silicon photonic crystals up five periods thick scale.
Deep etching methods applied to semiconductors allow the fabrication of two-dimensional and three-dimensional photonic crystals. The use chemical, plasma, focused ion beam etch silicon is reviewed.
Localized light wave states in the photonic band gaps two-dimensional octagonal and decagonal quasiperiodic dielectric media are investigated by considering corresponding approximant structures. The structure effects on local resonances at high-symmetry centers studied terms of interscatterer correlation coupling strength between neighbor scatterers is analyzed as a function symmetry order, contrast, scatterer size. It shown that an distance threshold can be defined for localization regime....
Light wave behaviors in two-dimensional quasiperiodic regular and generalized decagonal Penrose-tiling dielectric media, which display similar long range structure order different local configurations, are studied comparatively relation with both global orders through the approximant structures. We show that these structures generate analogous photonic band gaps, determined by lattice average order. localization, frequency levels lying inside main occurs regions of high symmetry patterns...
The full-vector plane-wave method was used to calculate the bandgaps of photonic crystal fiber with triangular structure. transmission spectrum hollow-core fabricated by Yanshan University measured, and we obtained relation between intensity wavelength in visible region. In subsequent experiment, mode field patterns were observed. theoretical simulation is well consistent experimental result.
We investigated the phason-strain-field influences on electronic and vibrational properties of two icosahedral quasicrystals, Al-Li-Cu Al-Fe-Cu. For that purpose we performed low-temperature specific-heat measurements samples before after annealing treatments allowed strong phason-strain elimination. The specific heat for systems is found to be scarcely sensitive treatments, while displays a different behavior: it remains unchanged in Al-Li-Cu, but strongly reduced Al-Fe-Cu annealing....
We investigate the light wave states in octagonal and decagonal quasiperiodic metallic structures by considering their respective approximants at different orders. The mechanisms underlying behaviors are studied relation to various structure parameters configurations. show that formation of first passbands, delimit photonic band gaps determine plasma gaps, involves only lowest frequency resonance modes inside fat tiles, localization occurs due resonances high symmetry local centers as well...
Light confinement induced by resonant states in aperiodic photonic structures are interesting for many applications. A particular case of these resonances can be found 2D quasi-crystalline arrangements dielectric cylinders. These systems present a rather isotropic band gap as well isolated in-gap (as result spatially localized resonances). built high symmetry polygonal clusters that regarded molecules. In this paper we study the transmission properties slab glass cylinders arranged...
We study the electromagnetic wave propagation in a graphenelike triangular metallic photonic structure and show that, associated to trigonally warped Dirac cones, transport properties resulting from an incident beam at armchair edge display drastically different behaviors as compared results obtained for other analogous systems. Namely, $K$ point, only center lower cone side beams upper and, ${K}^{\ensuremath{'}}$ significant intensities. The expected are all strongly inhibited. This can be...
Ga ion implantation in the organic crystal (TMTSF)2PF6 (TMTSF: tetramethyl tetraselena fulvalene) is performed using focused beam. It shown that heavy-ion deep inside sample obtained for relatively weak energy. The electric conduction of impact areas, at first strongly reduced by irradiation, observed to be reinforced further implantation. behaviors Ga-rich zones can described a small polaron hopping model.
We study the behavior of organic material (TMTSF)2PF6 (TMTSF: tetramethyl tetraselena fulvalene) under focused Ga+ ion beam impact using conducting probe atomic force microscopy (CP-AFM) and secondary mass spectrometry. The crystals are exposed to a 25 keV with sample native surface both perpendicular slightly tilted incident axis, where drastically different etching effects observed. Moreover, very large implantation depth, as compared conventional substrates, is obtained when set while...
In quasicrystalline AlMnSi alloys, the spin-glass contribution makes difficult correct evaluation of electronic density states (DOS) at Fermi level. The present investigation shows that low temperature specific heat varies as inverse square magnetic field, and so enables us to separate from one. d DOS level is reduced about 70% value observed in AlMn solid solution. This reduction can be understood resulting a sp-d resonant effect which opens pseudogap center virtual bound state. pseudogap,...
2D dielectric photonic quasicrystals can be designed to show isotropic band gaps. The system here studied is a quasiperiodic lattice made of silicon cylinders arranged as periodic unit cell based on decagonal approximant Penrose lattice. We analyze the bulk properties resulting well bright states excited in gap which correspond localized resonances electromagnetic field specific cylinder clusters Then we introduce controlled shear deformation breaks symmetry and evaluate width reduction...