A5067238403- High-pressure geophysics and materials
- Graphene research and applications
- Silicon Nanostructures and Photoluminescence
- Carbon Nanotubes in Composites
- Diamond and Carbon-based Materials Research
- Boron and Carbon Nanomaterials Research
- Glass properties and applications
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Crystal Structures and Properties
- Mechanical and Optical Resonators
- Material Dynamics and Properties
- Fullerene Chemistry and Applications
- Gas Sensing Nanomaterials and Sensors
- X-ray Diffraction in Crystallography
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Thermal properties of materials
- Luminescence Properties of Advanced Materials
- Solid-state spectroscopy and crystallography
- Advancements in Battery Materials
- Crystallization and Solubility Studies
- Ferroelectric and Piezoelectric Materials
- Advanced Thermoelectric Materials and Devices
- ZnO doping and properties
Institut Lumière Matière
2015-2024
Université Claude Bernard Lyon 1
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Université de Sherbrooke
2018-2024
Institut National des Sciences Appliquées de Lyon
2023-2024
Centre de Nanosciences et de Nanotechnologies
2018-2024
Laboratoire Nanotechnologies et Nanosystèmes
2020-2024
École Centrale de Lyon
2023
Groupe de Recherches sur l'Energétique des Milieux Ionisés
2023
Institut des Nanotechnologies de Lyon
2023
Through a systematic structural search we found an allotrope of carbon with Cmmm symmetry which predict to be more stable than graphite for pressures above 10 GPa. This material, refer as Z-carbon, is formed by pure sp(3) bonds and it provides explanation several features in experimental x-ray diffraction Raman spectra under pressure. The transition from Z-carbon can occur through simple sliding buckling graphene sheets. Our calculations that transparent wide band-gap semiconductor hardness...
This paper reviews the mechanical properties of graphene with particular attention to what is established and still uncertain. It clarifies thickness elastic constants, by also considering phonon frequencies, it argues that “best values” come from graphite, when available. Properties not available graphite include bending stiffness; this can be determined studies carbon nanotubes as well graphene. In many ways, provide access fundamental graphene, least because they are only form unsupported...
Perfectly crystalline solids are excellent heat conductors. Prominent counterexamples intermetallic clathrates, guest-host systems with a high potential for thermoelectric applications due to their ultralow thermal conductivities. Our combined experimental and theoretical investigation of the lattice dynamics particularly simple binary representative, ${\mathrm{Ba}}_{8}{\mathrm{Si}}_{46}$, identifies mechanism responsible reduction conductivity intrinsic perfect crystal structure. Above...
The high-pressure behavior of ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ is studied up to $40\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ using synchrotron x-ray diffraction and Raman spectroscopy in diamond anvil cells. A phase transformation from the monoclinic $\ensuremath{\beta}$-phase $(C2∕m)$ observed at a pressure above 20--$22\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. polymorph identified as $\ensuremath{\alpha}$-phase that isostructural with corundum ($R\overline{3}c$ symmetry) data. However,...
We investigate the cubic to tetragonal phase transition in pressure-temperature diagram of strontium titanate SrTiO3 (STO) by means Raman spectroscopy and X-ray diffraction on single crystal samples. experiments are performed at room temperature, 381 467 K up 53 GPa, 30 GPa 26 respectively. The observation superstructure reflections patterns provides evidence that undergoes all investigated temperatures a pressure-induced from I4/mcm phase, identical low-temperature phase. No other is...
The high pressure behavior of bundled $1.35\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ diameter single wall carbon nanotubes (SWNT) filled with ${\mathrm{C}}_{70}$ fullerenes (usually called peapods) has been investigated by Raman spectroscopy and compared the corresponding nonfilled SWNT. We show experimentally that two reversible pressure-induced transitions take place in compressed bundle first transition, $2--2.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ range,...
Exfoliated graphene and few layer samples supported on SiO(2) have been studied by Raman spectroscopy at high pressure. For immersed a alcohol mixture, an electron transfer of ∂n/∂P ∼ 8 × 10(12) cm(-2) GPa(-1) is observed for monolayer bilayer graphene, leading to giant doping values n 6 10(13) the maximum pressure 7 GPa. Three independent consistent proofs process are obtained from (i) evolution G-band 2D-band intensity ratio, (ii) coefficient frequency, (iii) 2D band components splitting...
The vibrational properties of double-walled carbon nanotubes (DWNTs) is investigated by high-pressure resonance Raman scattering up to 30 GPa in two different pressure-transmitting media (PTM): paraffin oil and NaCl. protection effect on the outer tube during compression verified .The collapse DWNTs experimentally observed for first time, showing be two-step: onset 1.56 nm diameter at ∼21 followed inner 0.86 a higher pressure ∼25 GPa. This observation supported calculations. We show that...
A low- to high-density pressure-driven phase transition in amorphous silicon is investigated by synchrotron x-ray diffraction the diamond anvil cell. Complementary atomistic molecular dynamics computer simulations provide insight into underlying structural transformations and allow us interpret structure factors obtained from experiment. During compression form of scattering function $S(Q)$ changes abruptly at $13.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, indicating significant...
The high-pressure behavior of polyiodides confined into the hollow core single-walled carbon nanotubes organized bundles has been studied by means Raman spectroscopy. Several regimes structural properties are observed for and under pressure. responses both compounds exhibit correlations over whole pressure range (0--17 GPa). Modifications, in particular, take place, respectively, between 1 2.3 GPa 7 9 nanotubes, depending on experiment. Differences one experiment to another discussed terms...
The effect of pressure – by definition a 3‐dimensional concept on 2‐dimensional systems brings number fundamental questions, which have been partly answered through newly engineered samples and experimental setups. In this review the high‐pressure Raman studies graphene, we will in particular underline importance presence supporting substrate its role for production biaxial strain conditions high experiments. shifts observed during these experiments may be related to induced rather than...
Recently the new family of spinel-structured nitrides and oxynitrides group 14 elements (Si, Ge, Sn) has been explored using high-pressure synthesis techniques. The solid-state compounds have high hardness, they are semiconducting materials that predicted to a wide direct band gap. Here we prepared corresponding gallium oxynitride spinel with ideal formula Ga3O3N. conditions stability phase were first-principles calculations, experimental study was realized combination laser-heated diamond...
Nanoparticles have more propensities for amorphization than their bulk counterparts, opening the opportunity to achieve amorphous states in well-known poor glass-former compounds. Classical size effects are often invoked explain such phenomenon. However, this argument is not sufficient cover all experimental results as functionalization effect. In work, Y2O3 nanoparticles of 7 nm diameter investigated under pressure. Special care taken on surface state particles by comparing pressure-induced...
Pressure and temperature phase transitions of nanomaterials often differ significantly from those their bulk parents, offering novel approaches for the engineering original materials. The importance or even dominance surface atoms in nanoworld enhances effects environment, geometry, intercalation. In present article, we explore current knowledge these effects, as evidenced high pressure diagrams such nanocrystals, carbon nanotubes, fullerites, graphene, other 2D systems, well nanoporous...
The Porous germanium Efficient Epitaxial LayEr Release (PEELER) process is introduced allowing the fabrication of wafer scale detachable monocrystalline Ge nanomembranes compatible with III–V material growth on porous and substrate reuse.