A5081256814- Graphene research and applications
- Topological Materials and Phenomena
- 2D Materials and Applications
- Nonlinear Optical Materials Studies
- Fullerene Chemistry and Applications
- Quantum and electron transport phenomena
- MXene and MAX Phase Materials
- Magnetic properties of thin films
- Advanced Thermoelectric Materials and Devices
- Quantum Dots Synthesis And Properties
- Inorganic Chemistry and Materials
- Surface and Thin Film Phenomena
- Nonlinear Optical Materials Research
- Magnetic and transport properties of perovskites and related materials
- Polymer Nanocomposite Synthesis and Irradiation
- Semiconductor materials and devices
- Physics of Superconductivity and Magnetism
- Carbon Nanotubes in Composites
- Photochemistry and Electron Transfer Studies
- Reservoir Engineering and Simulation Methods
- 3D Printing in Biomedical Research
- Advanced Photocatalysis Techniques
- Photonic Crystals and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Non-Destructive Testing Techniques
National Centre of Scientific Research "Demokritos"
2013-2024
Technological Educational Institute of Central Greece
2016
Foundation for Research and Technology Hellas
2004-2008
University of Patras
2005-2008
National Hellenic Research Foundation
2007
Ultrathin (sub-monolayer to 12 monolayers) AlN nanosheets are grown epitaxially by plasma assisted molecular beam epitaxy on Ag(111) single crystals. Electron diffraction and scanning tunneling microscopy provide evidence that Ag adopts a graphite-like hexagonal structure with larger lattice constant compared bulk-like wurtzite AlN. This claim is further supported ultraviolet photoelectron spectroscopy indicating reduced energy bandgap as expected for
Atomically thin MoSe<sub>2</sub> films grown epitaxially on AlN by MBE have high crystallinity, smooth surface and interface morphology, sizable semiconductor band gap for use in nanoelectronics.
Using molecular beam epitaxy, atomically thin 2D semiconductor HfSe2 and MoSe2/HfSe2 van der Waals heterostructures are grown on AlN(0001)/Si(111) substrates. Details of the electronic band structure imaged by in-situ angle resolved photoelectron spectroscopy indicating a high quality epitaxial layer. High-resolution surface tunneling microscopy supported first principles calculations provides evidence an ordered Se adlayer, which may be responsible for reduction measured workfunction...
The electronic band structure of monolayer (4 × 4) silicene on Ag(111) is imaged by angle resolved photoelectron spectroscopy. A dominant hybrid surface metallic observed to be located near the bulk Ag sp-band which also faintly visible. two-dimensional character has been distinguished against means photon energy dependence experiments. exhibits a steep linear dispersion around K¯Ag point and saddle M¯Ag resembling π-band in graphene.
In this work, a structural analysis of Ge layers deposited by molecular beam epitaxy (MBE) on Ag(1 1 1) surfaces with and without an AlN buffer layer have been investigated x-ray Absorption Spectroscopy (XAS) at the Ge-K edge. For h-AlN interatomic Ge–Ge distance Å is found, typical 2-Dimensional in agreement theoretical predictions for free standing low-buckled Germanene presented literature. First principles calculations, performed density functional theory (DFT) framework, supported...
Molecular beam epitaxy of 2D metal TaSe2/2D MoSe2 (HfSe2) semiconductor heterostructures on epi-AlN(0001)/Si(111) substrates is reported. Electron diffraction reveals an in-plane orientation indicative van der Waals epitaxy, whereas electronic band imaging supported by first-principles calculations and X-ray photoelectron spectroscopy indicate the presence a dominant trigonal prismatic 2H-TaSe2 phase minor contribution from octahedrally coordinated TaSe2, which present in TaSe2/AlN...
A series of novel [60]fullerene-ferrocene and [60]fullerene-porphyrin dyads, in which a fullerene an electron donating moiety are attached through flexible triethylene glycol linker synthesized their nonlinear optical (NLO) response studied. Specifically, the third-order susceptibility chi(3) all derivatives measured toluene solutions by Kerr effect (OKE) technique using 532 nm, 35 ps laser pulses second hyperpolarizability gamma determined. All dyads studied exhibit enhancement NLO compared...
Spin-to-charge conversion (SCC) involving topological surface states (TSS) is one of the most promising routes for highly efficient spintronic devices terahertz (THz) emission. Here, THz generation generally occurs mainly via SCC consisting in dynamical spin injection into spin-locked TSS. In this work, we demonstrate sizable emission from a nanometric thick insultator (TI)/ferromagnetic junction - SnBi$_2$Te$_4$/Co specifically designed to avoid bulk band crossing with TSS at Fermi level,...
Germanium deposited on single-crystal Ag(111) substrates at about 1/3-monolayer coverage forms a stable $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R{30}^{\ensuremath{\circ}}$ superstructure as seen by reflection high-energy electron diffraction. In situ angle resolved photoelectron spectroscopy reveals rich band structure consisting of conelike features that cross the Fermi surface center ($\overline{\ensuremath{\Gamma}}$ points) Brillouin zone (SBZ), exhibiting high dispersion...
Bi2Se3 topological insulators (TIs) are grown on AlN(0001)/Si(111) substrates by molecular beam epitaxy. In a one-step growth at optimum temperature of 300 °C, bonds strongly with AlN without forming interfacial reaction layers. This produces high epitaxial quality single crystals perfect registry the substrate and abrupt interfaces, allowing thickness scaling down to three quintuple layers (QL) jeopardizing film quality. It is found angle-resolved photoelectron spectroscopy that,...
Abstract Films of gold nanoscaled islands with thicknesses ranging between 0.5 and 15 nm were prepared by thermal evaporation onto untreated aminosilane‐pretreated glass substrates. Post‐deposition annealing was found to modify the morphological characteristics (e.g., average island area height, inter‐island distance, etc.), resulting in changes localized surface plasmon resonance (SPR) and, therefore, modifying nonlinear optical (NLO) response films. The NLO both unannealed annealed (20 h...
The dispersion of the otherwise insoluble C60 fullerene in water is discussed. Amphiphilic block copolymers, namely, polystyrene-b-polyethylene oxide (PS-PEO), were found to be able disperse aqueous solutions, where polymer forms micelles with a hydrophobic PS core. preparation protocol final solutions was play crucial role ability copolymer molecules. containing aggregates studied using optical spectroscopy, light scattering, and scanning electron microscopy. In addition, their limiting...
Topological semimetals host interesting new types of low-energy quasiparticles such as type-I and type-II Dirac Weyl fermions. Type-III topological can emerge exactly at the border between II, characterized by a line-like Fermi surface flat energy dispersion near band crossing. Here, we theoretically predict that 1T-HfTe2 1T-ZrTe2 transition metal dichalcogenides are DSMs, respectively. By alloying two materials, HfxZr1−xTe2 alloy with type-III cone emerges x = 0.2, in combination 1%...
In the last decades, numerous analytical techniques have been extensively used for compositional analysis of objects archaeological interest. However, on cultural heritage objects, application most techniques, such as AAS, XRD, ICP-MS, NAA and SEM-EDX is destructive a significant amount sample consumed. Furthermore, many those are expensive time-demanding, mainly due to preparation. this work, LIBS applied an alternative technique qualitative quantitative elemental black glaze main body...
Growth of few-layer graphene using ferrocene as precursor by chemical vapor deposition is reported. The growth did not involve any additional carbon or catalyst source external hydrocarbon gases. Parametric investigation was performed different conditions, namely, varying temperature from 600 to1000 °C, and duration 5 min to 3 h, well fast quenching gradual cooling after the thermal treatment, in order examine effect on quality produced graphene. took place silicon wafers resulted, under...
Photonic crystal structuring has emerged as an advanced method to enhance solar light harvesting by metal oxide photocatalysts along with rational compositional modifications of the materials’ properties. In this work, surface functionalization TiO2 photonic crystals blue luminescent graphene quantum dots (GQDs), n–π* band at ca. 350 nm, is demonstrated a facile, environmental benign promote photocatalytic activity combination slow photon-assisted trapping GQD-TiO2 interfacial electron...
Topological insulators are good candidates for charge to spin conversion with high efficiency due their spin-polarized topological surface states (TSSs). In this work, we provide experimental evidence two-dimensional (2D) TSSs in ${(\mathrm{Sn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4})}_{n} {({\mathrm{Bi}}_{2}{\mathrm{Te}}_{3})}_{m}$ natural van der Waals superlattices grown by molecular beam epitaxy using angle resolved photoelectron spectroscopy and magnetotransport. While the overlap bulk...
One monolayer semimetallic HfTe2 thin films are grown on three substrates with different electronic properties in order to study the substrate effect structure of epilayer. Angle resolved photoelectron spectroscopy measurements indicate that band features identical all cases, providing evidence epilayer does not interact any form hybridized bands and feature originates from material itself. However, a shift energy is observed among which attributed electron doping. This paves way for...