A5077440682- Photonic and Optical Devices
- Photonic Crystals and Applications
- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Advanced Fiber Laser Technologies
- Graphene research and applications
- Optical Coatings and Gratings
- Molecular Junctions and Nanostructures
- Optical Network Technologies
- Organic Electronics and Photovoltaics
- Quantum optics and atomic interactions
- Thin-Film Transistor Technologies
- Conducting polymers and applications
- Metal and Thin Film Mechanics
- Nanowire Synthesis and Applications
- Nonlinear Optical Materials Studies
- GaN-based semiconductor devices and materials
- 2D Materials and Applications
- Diamond and Carbon-based Materials Research
- Quantum Dots Synthesis And Properties
- Mechanical and Optical Resonators
- Laser-Matter Interactions and Applications
- Thermal Radiation and Cooling Technologies
- Perovskite Materials and Applications
- Advanced Fiber Optic Sensors
University of Ioannina
2016-2025
Technion – Israel Institute of Technology
2022
University of Cambridge
2007-2017
European Space Research and Technology Centre
2010
Aristotle University of Thessaloniki
2010
TU Dresden
2010
Leibniz Institute of Polymer Research
2010
Moscow Institute of Thermal Technology
2008
Massachusetts Institute of Technology
2002-2007
Ludwig-Maximilians-Universität München
2007
We present the science and technology roadmap for graphene, related two-dimensional crystals, hybrid systems, targeting an evolution in technology, that might lead to impacts benefits reaching into most areas of society. This was developed within framework European Graphene Flagship outlines main targets research as best understood at start this ambitious project. provide overview key aspects graphene materials (GRMs), ranging from fundamental challenges a variety applications large number...
We investigate graphene and layers on different substrates by monochromatic white-light confocal Rayleigh scattering microscopy. The image contrast depends sensitively the dielectric properties of sample as well substrate geometry can be described quantitatively using complex refractive index bulk graphite. For a few (<6), increases linearly with thickness. data adequately understood considering samples behaving superposition single sheets that act independent two-dimensional electron gases....
Surface-enhanced Raman scattering (SERS) exploits surface plasmons induced by the incident field in metallic nanostructures to significantly increase intensity. Graphene provides ideal prototype two-dimensional (2d) test material investigate SERS. Its spectrum is well-known, graphene samples are entirely reproducible, height controllable down atomic scale, and can be made virtually defect-free. We report SERS from graphene, depositing arrays of Au particles well-defined dimensions on a...
The nitrides of most the group IVb-Vb-VIb transition metals (TiN, ZrN, HfN, VN, NbN, TaN, MoN, WN) constitute unique category conductive ceramics. Having substantial electronic conductivity, exceptionally high melting points and covering a wide range work function values, they were considered for variety applications, which include diffusion barriers in metallizations integrated circuits, Ohmic contacts on compound semiconductors, thin film resistors, since early eighties. Among them, TiN...
Graphene is ideally suited for photonic and optoelectronic applications, with a variety of photodetectors (PDs) in the visible, near-infrared (NIR), THz reported to date, as well thermal detectors mid-infrared (MIR). Here, we present room temperature-MIR-PD where pyroelectric response LiNbO3 crystal transduced high gain (up 200) into resistivity modulation graphene, leading temperature coefficient resistance up 900%/K, two orders magnitude higher than state art, device area 300x300um2. This...
Although the detection of light at terahertz (THz) frequencies is important for a large range applications, current detectors typically have several disadvantages in terms sensitivity, speed, operating temperature, and spectral range. Here, we use graphene as photoactive material to overcome all these limitations one device. We introduce novel detector radiation that exploits photothermoelectric (PTE) effect, based on design employs dual-gated, dipolar antenna with gap 100 nm. This...
The combination of plasmonic nanoparticles and graphene enhances the responsivity spectral selectivity graphene-based photodetectors. However, small area metal-graphene junction, where induced electron-hole pairs separate, limits photoactive region to submicron length scales. Here, we couple with a grating exploit resulting surface plasmon polaritons deliver collected photons junction metal-graphene-metal photodetector. This gives 400% enhancement 1000% increase in length, combined tunable...
We prove that an adiabatic theorem generally holds for slow tapers in photonic crystals and other strongly grated waveguides with arbitrary index modulation, exactly as conventional waveguides. This provides a guaranteed pathway to efficient broad-bandwidth couplers with, e.g., uniform show transmission can only occur, however, if the operating mode is propagating (nonevanescent) guided at every point taper. Moreover, we demonstrate how straightforward taper designs violate these conditions,...
The ideas of the linear combination atomic orbitals (LCAO) method, well known from study electrons, is extended to classical wave case. Mie resonances isolated scatterer in case, are analogous localized eigenstates electronic matrix elements two-dimensional tight-binding (TB) Hamiltonian obtained by fitting ab initio results. transferability TB model tested reproducing accurately band structure different 2D lattices, with and without defects, thus proving that parameters can be used other...
A class of axially uniform waveguides is introduced, employing a new mechanism to guide light inside low-index dielectric material without the use photonic band gap, and simultaneously exhibiting subwavelength modal size very slow group velocity over an unusually large frequency bandwidth. Their basis presence plasmonic modes on interfaces between regions flat unpatterned surface bulk metallic substrate. These novel allow for easy broadband coupling exhibit absorption losses limited only by...
▪ Abstract Atomistic aspects of dynamic fracture in a variety brittle crystalline, amorphous, nanophase, and nanocomposite materials are reviewed. Molecular dynamics (MD) simulations, ranging from million to 1.5 billion atoms, performed on massively parallel computers using highly efficient multiresolution algorithms. These simulations shed new light (a) branching, deflection, arrest cracks; (b) growth nanoscale pores ahead the crack how coalesce with cause fracture; (c) influence these...
Graphene’s high mobility and Fermi velocity, combined with its constant light absorption in the visible to far-infrared range, make it an ideal material fabricate high-speed ultrabroadband photodetectors. However, precise mechanism of photodetection is still debated. Here, we report wavelength polarization-dependent measurements metal–graphene–metal This allows us quantify control relative contributions both photothermo- photoelectric effects, adding overall photoresponse. paves way for a...
We report vertically illuminated, resonant cavity enhanced, graphene–Si Schottky photodetectors (PDs) operating at 1550 nm. These exploit internal photoemission the interface. To obtain spectral selectivity and enhance responsivity, PDs are integrated with an optical cavity, resulting in multiple reflections resonance, enhanced absorption graphene. get a wavelength-dependent photoresponse external (internal) responsivity ∼20 mA/W (0.25A/W). The may be further tuned by varying wavelength. Our...
We fabricate a saturable absorber mirror by coating graphene film on an output coupler mirror. This is then used to obtain Q-switched mode-locking from diode pumped linear cavity waveguide laser inscribed in Ytterbium-doped Bismuthate Glass, with high slope and optical conversion efficiencies. The produces mode-locked pulses at 1039nm, 1.5GHz repetition rate average 202mW power. performance due the combination of quality glass.
Abstract Integrating and manipulating the nano-optoelectronic properties of Van der Waals heterostructures can enable unprecedented platforms for photodetection sensing. The main challenge infrared photodetectors is to funnel light into a small nanoscale active area efficiently convert it an electrical signal. Here, we overcome all those challenges in one device, by efficient coupling plasmonic antenna hyperbolic phonon-polaritons hexagonal-BN highly concentrate mid-infrared graphene p n...
We determine the Raman scattering efficiency of $G$ and $2D$ peaks in graphene. Three substrates are used: silicon covered with 300 or 90 nm oxide, calcium fluoride (CaF${}_{2}$). On Si/SiO${}_{x}$, areas peak show a strong dependence on substrate due to interference effects, while CaF${}_{2}$ no significant is detected. Unintentional doping reduced by placing graphene CaF${}_{2}$. comparison 322 cm${}^{\ensuremath{-}1}$ area At 2.41 eV,...
Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged a category of promising alternative plasmonic materials. In this work, we show that ternary nitrides TixTa1−xN, TixZr1−xN, TixAl1−xN, ZrxTa1−xN share the important features with their counterparts, while having additional asset exceptional spectral tunability in entire visible (400–700 nm) UVA (315–400 ranges depending on net valence electrons. particular, demonstrate can exhibit maximum field enhancement factors...
Abstract Layered materials (LMs) produced by liquid phase exfoliation (LPE) can be used as building blocks for optoelectronic applications. However, when compared with mechanically exfoliated flakes, or films prepared chemical vapor deposition (CVD), LPE-based printed devices are limited mobility, defects and trap states. Here, we present a scalable fabrication technique combining CVD LPE LMs to overcome such limitations. We use black phosphorus inks, inkjet-printed on graphene Si/SiO 2 ,...
The integration of optoelectronic devices, such as transistors and photodetectors (PDs), into wearables textiles is great interest for applications healthcare physiological monitoring. These require flexible/wearable systems adaptable to body motions, thus materials conformable non-planar surfaces, able maintain performance under mechanical distortions. Here, fibre PDs are prepared by combining rolled graphene layers photoactive perovskites. Conductive fibres (~500 Ωcm
Abstract Layered material heterostructures (LMHs) can be used to fabricate electroluminescent devices operating in the visible spectral region. A major advantage of LMH-based light emitting diodes (LEDs) is that electroluminescence (EL) emission tuned across different exciton complexes (e.g. biexcitons, trions, quintons) by controlling charge density. However, these have an EL quantum efficiency as low ∼10 −4 %. Here, we show superacid bis-(triuoromethane)sulfonimide (TFSI) treatment...
The authors describe simulation approaches that seamlessly combine continuum mechanics with atomistic simulations and quantum mechanics. They also discuss computational visualization issues associated these on massively parallel computers. Scientists are combining through integrated multidisciplinary efforts so a single couples diverse length scales. However, the complexity of hybrid schemes poses an unprecedented challenge, developments in scalable algorithms as well interactive immersive...
We investigate the photonic properties of two-dimensional nanotube arrays for photon energies up to 40 eV and unveil physics two distinct applications: deep-UV crystals total visible absorbers. find three main regimes: small intertube spacing 20−30 nm, we obtain strong Bragg scattering band gaps in range 25∼35 eV. For intermediate 40−100 bands anticross with graphite plasmon resulting into a complex structure, generally reduced scattering. large >150 gap moves decreases due absorption. This...
A universal strategy for efficient light trapping through the incorporation of gold nanorods on electron transport layer (rear) organic photovoltaic devices is demonstrated. Utilizing photons that are transmitted active a bulk heterojunction device and would otherwise be lost, significant enhancement in power conversion efficiency (PCE) poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)]:phenyl‐C 71 ‐butyric acid methyl ester (PCDTBT:PC BM)...