Olivia MAUGUIN
@cnrs.fr
Scopus Publications
Scopus Publications
Rana Ghannam, Loic Coulomb, Adrien Moll, David Bérardan, David Maurin, Jean-Louis Bantignies, Olivia Mauguin, Antonio Vieira e Silva, Bertrand Rebière, Benjamin Villeroy,et al.
Elsevier BV
Shimul Kanti Nath, Ibrahim Turan, Léonard Desvignes, Ludovic Largeau, Olivia Mauguin, Marc Túnica, Michele Amato, Charles Renard, Géraldine Hallais, Dominique Débarre,et al.
Wiley
Superconductivity in ultradoped Si1−xGex:B epilayers is demonstrated by nanosecond laser doping, which allows introducing substitutional B concentrations well above the solubility limit and up to 7 at%. A Ge fraction x ranging from 0 to 0.21 is incorporated in Si:B: 1) through a precursor gas, by gas immersion laser doping; 2) by ion implantation, followed by nanosecond laser annealing; and 3) by ultrahigh‐vacuum‐chemical vapor deposition growth of a thin Ge layer, followed by nanosecond laser annealing. The 30 and 75 nm‐thick Si1−xGex:B epilayers display superconducting critical temperatures Tc tuned by B and Ge between 0 and 0.6 K. Within Bardeen Cooper Schrieffer (BCS) weak‐coupling theory, Tc evolves exponentially with both the density of states and the electron–phonon potential. While B doping affects both, through the increase of the carrier density and the tensile strain, Ge incorporation allows addressing independently the lattice deformation influence on superconductivity. To estimate the lattice parameter modulation with B and Ge, Vegard's law is validated for the ternary SiGeB bulk alloy by density functional theory calculations. Its validity is furthermore confirmed experimentally by X‐ray diffraction. A global linear dependence of Tc versus lattice parameter, common for both Si:B and Si1−xGex:B, with δTc/Tc ≈ 50% for δa/a ≈1%, is highlighted.
Jérémie Aubineau, Fleurice Parat, Ernest Chi Fru, Radouan El Bamiki, Olivia Mauguin, Fabien Baron, Marc Poujol, and Michel Séranne
Frontiers Media SA
Emerging evidence suggests that U-Pb and Lu-Hf ages of sedimentary apatite group minerals are often younger than their biostratigraphic ages. However, U-Pb dating of exquisitely preserved carbonate fluorapatite (CFA) is rare. The Upper Cretaceous/Paleogene marine sedimentary rocks of the Moroccan High Atlas host phosphate-rich sediments bracketed by calcareous nannofossil Zones (NP4-NP9) of late Danian to Thanetian age. Here, we use a laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to decipher whether CFA minerals are suitable for U-Pb chronostratigraphy and whether they can reveal the sedimentary and seawater history from which they formed. U-Pb dating of the CFA grains yields ages of 42.9 ± 1.3 Ma (MSWD = 2.3) and 35.7 ± 2.8 Ma (MSWD = 1.3) from three distinct phosphate-rich beds, being >15 million years younger than the expected biostratigraphic age. Combined scanning electron microscopy, X-ray diffraction, and infrared spectroscopy analyses, associate the Mg-rich clay minerals sepiolite and palygorskite, with micro-CFA crystals, while LA-ICP-MS trace element, rare earth element, and yttrium content for primary CFA grains, collectively point to long-term early diagenetic adsorption from oxygenated seawater-dominated porewater fluids. Authigenic clay minerals display a seawater-like pattern, with negligible U concentrations suggesting limited clay mineral influence on U-Pb dating of the CFA crystals. Considering the absence of extensive post-depositional alteration, we propose that because of their large surface area, the µm-sized CFA crystallites facilitated real-time surface adsorption and desorption of elements and diffusion processes. These conditions generated long-term open system connection of sediments with overlying seawater, enabling continuous U-Pb exchange for 15–25 Myr after phosphate precipitation. The data suggest that system closure was potentially associated with sediment lithification and the Atlas orogeny, pointing to stable oxygenation of shallow marine waters along the eastern passive margin of the central Atlantic Ocean in the Paleogene.
Jérémie Aubineau, Fleurice Parat, Abdellatif Elghali, Otmane Raji, Aissam Addou, Clément Bonnet, Manuel Muñoz, Olivia Mauguin, Fabien Baron, Moulay Brahim Jouti,et al.
Elsevier BV
K. Pantzas, G. Beaudoin, M. Bailly, A. Martin, A. Grisard, D. Dolfi, O. Mauguin, L. Largeau, I. Sagnes, and G. Patriarche
Informa UK Limited
ABSTRACT The mechanical stability of commercial GaP/Si templates during thermal annealing and subsequent growth of GaP and AlGaP using metal-organic chemical-vapour deposition is investigated. Although the as-grown GaP layer of the template originally presents an excellent surface morphology, annealing at temperatures between 645 C to 845 C to remove the native oxide prior to growth leads to plastic relaxation, accompanied by a variety of defects, including a dense grid of micro-twins. These micro-twins detrimentally affect GaP and AlGaP layers grown subsequently on the template.
Ahmed Ben Slimane, Amadeo Michaud, Olivia Mauguin, Xavier Lafosse, Adrien Bercegol, Laurent Lombez, Jean‐Christophe Harmand, and Stéphane Collin
Wiley
AbstractWe report on AlGaAs‐based heterojunction solar cells grown by solid source molecular beam epitaxy (MBE). We investigate InGaP and AlGaAs material quality and we demonstrate significant efficiency improvements by combining the best of each alloy: a thick p‐AlGaAs base with tunable bandgap, and a thin 50 nm n‐InGaP emitter separated by a thin intrinsic AlGaAs layer. We report a certified solar cell conversion efficiency of 18.7% with a 2‐μm‐thick AlGaAs layer and a bandgap of 1.73 eV, suitable for high efficiency Si‐based tandem devices.
D. Pelati, G. Patriarche, L. Largeau, O. Mauguin, L. Travers, F. Brisset, F. Glas, and F. Oehler
Elsevier BV
Quang Chieu Bui, Ludovic Largeau, Martina Morassi, Nikoletta Jegenyes, Olivia Mauguin, Laurent Travers, Xavier Lafosse, Christophe Dupuis, Jean-Christophe Harmand, Maria Tchernycheva,et al.
MDPI AG
The development of sensors working in a large range of temperature is of crucial importance in areas such as monitoring of industrial processes or personal tracking using smart objects. Devices integrating GaN/Ga2O3 core/shell nanowires (NWs) are a promising solution for monitoring carbon monoxide (CO). Because the performances of sensors primarily depend on the material properties composing the active layer of the device, it is essential to control them and achieve material synthesis in the first time. In this work, we investigate the synthesis of GaN/Ga2O3 core-shell NWs with a special focus on the formation of the shell. The GaN NWs grown by plasma-assisted molecular beam epitaxy, are post-treated following thermal oxidation to form a Ga2O3-shell surrounding the GaN-core. We establish that the shell thickness can be modulated from 1 to 14 nm by changing the oxidation conditions and follows classical oxidation process: A first rapid oxide-shell growth, followed by a reduced but continuous oxide growth. We also discuss the impact of the atmosphere on the oxidation growth rate. By combining XRD-STEM and EDX analyses, we demonstrate that the oxide-shell is crystalline, presents the β-Ga2O3 phase, and is synthesized in an epitaxial relationship with the GaN-core.
D. Pelati, G. Patriarche, O. Mauguin, L. Largeau, L. Travers, F. Brisset, F. Glas, and F. Oehler
Elsevier BV
Ahmed Ben Slimane, Amadeo Michaud, Adrien Bercegol, Julie Goffard, Olivia Mauguin, Xavier Lafosse, Karolien Saliou, Laurent Lombez, Jean-Christophe Harmand, and Stephane Collin
IEEE
Today’s most efficient III-V solar cells rely on InGaP materials and are mostly grown by metal organic vapor phase epitaxy (MOVPE). Here, we report on an AlGaAs-based solar cell grown by solid source molecular beam epitaxy (MBE), with a certified conversion efficiency of 18.7%, and a 1.73eV bandgap designed for Si-based dual junction tandem devices. Material characterizations were carried out using Hall effect, secondary-ion mass spectrometry (SIMS) and X-Ray diffraction for the optimization of growth parameters of two conventional homojunction AlGaAs and InGaP solar cells. External quantum efficiencies (EQE) and I-V measurements demonstrate issues related to n-type AlGaAs and p-type InGaP layers. We show an important efficiency increase by merging the best of each structure: a thick p-AlGaAs base with tunable bandgap, and a thin 50 nm InGaP emitter.
G. Arregui, O. Ortíz, M. Esmann, C. M. Sotomayor-Torres, C. Gomez-Carbonell, O. Mauguin, B. Perrin, A. Lemaître, P. D. García, and N. D. Lanzillotti-Kimura
AIP Publishing
Inspired by concepts developed for fermionic systems in the framework of condensed matter physics, topology and topological states are recently being explored also in bosonic systems. Recently, some of these concepts have been successfully applied to acoustic phonons in nanoscale multilayered systems. The reported demonstration of confined topological phononic modes was based on Raman scattering spectroscopy [M. Esmann et al., Phys. Rev. B 97, 155422 (2018)], yet the resolution did not suffice to determine lifetimes and to identify other acoustic modes in the system. Here, we use time-resolved pump-probe measurements using an asynchronous optical sampling (ASOPS) technique to overcome these resolution limitations. By means of one-dimensional GaAs/AlAs distributed Bragg reflectors (DBRs) used as building blocks, we engineer high frequency (∼200 GHz) topological acoustic interface states. We are able to clearly distinguish confined topological states from stationary band edge modes. The generation/detection scheme reflects the symmetry of the modes directly through the selection rules, evidencing the topological nature of the measured confined state. These experiments enable a new tool in the study of the more complex topology-driven phonon dynamics such as phonon nonlinearities and optomechanical systems with simultaneous confinement of light and sound.
D. Pelati, O. Mauguin, L. Largeau, F. Brisset, F. Glas, and F. Oehler
Elsevier BV
D. Pelati, G. Patriarche, O. Mauguin, L. Largeau, F. Brisset, F. Glas, and F. Oehler
American Chemical Society (ACS)
We use high-resolution optical microscopy to characterize in situ the processes at play during the Al-induced crystallization of amorphous Ge. In addition to the well-established aluminum-induced layer exchange (ALILE) process, we demonstrate the existence of another crystallization mechanism with different kinetics and spatial extension using in situ monitoring. Further, ex situ characterizations show that both processes are active in our samples. The ALILE process is found to create a single Ge layer and 111-oriented crystallites in our growth conditions, while the other crystallization process yields a double Ge layer with mixed 111 and 100 orientations in the bottom layer, while the top layer remains amorphous. This work underlines the importance of in situ monitoring for the understanding and modeling of metal-induced crystallization.
Michał Studniarek, Salia Cherifi‐Hertel, Etienne Urbain, Ufuk Halisdemir, Rémi Arras, Beata Taudul, Filip Schleicher, Marie Hervé, Charles‐Henri Lambert, Abbass Hamadeh,et al.
Wiley
Spin‐polarized charge transfer at the interface between a ferromagnetic (FM) metal and a molecule can lead to ferromagnetic coupling and to a high spin polarization at room temperature. The magnetic properties of these interfaces can not only alter those of the ferromagnet but can also stabilize molecular spin chains with interesting opportunities toward quantum computing. With the aim to enhance an organic spintronic device's functionality, external control over this spin polarization may thus be achieved by altering the ferromagnet/molecule interface's magnetic properties. To do so, the magnetoelectric properties of an underlying ferroelectric/ferromagnetic interface are utilized. Switching the ferroelectric polarization state of a PbZr0.2Ti0.8O3 (PZT) bottom layer within a PZT/Co/FePc‐based (Pc ‐ phthalocyanine) device alters the X‐ray magnetic circular dichroism of the Fe site within the phthalocyanine molecular top layer. Thus, how to electrically alter the magnetic properties of an interface with high spin polarization at room temperature is demonstrated. This expands electrical control over spin‐polarized FM/molecule interfaces, which is first demonstrated using ferroelectric molecules, to all molecular classes.
Romain Cariou, Wanghua Chen, Jean-Luc Maurice, Jingwen Yu, Gilles Patriarche, Olivia Mauguin, Ludovic Largeau, Jean Decobert, and Pere Roca i Cabarrocas
Springer Science and Business Media LLC
AbstractThe integration of III-V semiconductors with silicon is a key issue for photonics, microelectronics and photovoltaics. With the standard approach, namely the epitaxial growth of III-V on silicon, thick and complex buffer layers are required to limit the crystalline defects caused by the interface polarity issues, the thermal expansion and lattice mismatches. To overcome these problems, we have developed a reverse and innovative approach to combine III-V and silicon: the straightforward epitaxial growth of silicon on GaAs at low temperature by plasma enhanced CVD (PECVD). Indeed we show that both GaAs surface cleaning by SiF4 plasma and subsequent epitaxial growth from SiH4/H2 precursors can be achieved at 175 °C. The GaAs native oxide etching is monitored with in-situ spectroscopic ellipsometry and Raman spectroscopy is used to assess the epitaxial silicon quality. We found that SiH4 dilution in hydrogen during deposition controls the layer structure: the epitaxial growth happens for deposition conditions at the transition between the microcrystalline and amorphous growth regimes. SIMS and STEM-HAADF bring evidences for the interface chemical sharpness. Together, TEM and XRD analysis demonstrate that PECVD enables the growth of high quality relaxed single crystal silicon on GaAs.
Konstantinos Pantzas, Grégoire Beaudoin, Gilles Patriarche, Ludovic Largeau, Olivia Mauguin, Giulia Pegolotti, Angela Vasanelli, Ariane Calvar, Maria Amanti, Carlo Sirtori,et al.
IOP Publishing
A procedure that produces sub-nanometrically resolved chemical mappings of MOCVD-grown InGaAs/InAlAs/InP quantum cascade lasers is presented. The chemical mappings reveal that, although the structure is lattice-matched to InP, the InAlAs barriers do not attain the nominal aluminum content—48%—and are, in fact, InGaAlAs quaternaries. This information is used to adjust the aluminum precursor flow and fine-tune the composition of the barriers, resulting in a significant improvement of the fabricated lasers.
V Kumaresan, L Largeau, F Oehler, H Zhang, O Mauguin, F Glas, N Gogneau, M Tchernycheva, and J-C Harmand
IOP Publishing
We study the self-induced growth of GaN nanowires on silica. Although the amorphous structure of this substrate offers no possibility of an epitaxial relationship, the nanowires are remarkably aligned with the substrate normal whereas, as expected, their in-plane orientation is random. Their structural and optical characteristics are compared to those of GaN nanowires grown on standard crystalline Si (111) substrates. The polarity inversion domains are much less frequent, if not totally absent, in the nanowires grown on silica, which we find to be N-polar. This work demonstrates that high-quality vertical GaN nanowires can be elaborated without resorting to bulk crystalline substrates.
K. Pantzas, D.J. Rogers, P. Bove, V.E. Sandana, F.H. Teherani, Y. El Gmili, M. Molinari, G. Patriarche, L. Largeau, O. Mauguin,et al.
Elsevier BV
V Kumaresan, L Largeau, F Oehler, H Zhang, O Mauguin, F Glas, N Gogneau, M Tchernycheva, and J-C Harmand
IOP Publishing
Enhanced catalyst-free nucleation of GaN nanowires on amorphous Al 2 O 3 by plasma-assisted molecular beam epitaxy Abstract We study the self-induced growth of GaN nanowires on silica. Although the amorphous structure of this substrate offers no possibility of an epitaxial relationship, the nanowires are remarkably aligned with the substrate normal whereas, as expected, their in-plane orientation is random. Their structural and optical characteristics are compared to those of GaN nanowires grown on standard crystalline Si ( 111 ) substrates. The polarity inversion domains are much less frequent, if not totally absent, in the nanowires grown on silica, which we fi nd to be N-polar. This work demonstrates that high-quality vertical GaN nanowires can be elaborated without resorting to bulk crystalline substrates.
Yann Cohin, Frank Glas, Andrea Cattoni, Sophie Bouchoule, Olivia Mauguin, Ludovic Largeau, Gilles Patriarche, Elin Søndergård, and Jean-Christophe Harmand
American Chemical Society (ACS)
Fiber-textured polycrystalline silicon thin films have demonstrated their interest as seed layers for the epitaxial growth of high-quality materials on substrates such as glass or plastics. In the present work, we report a comprehensive study of the aluminum-induced crystallization (AIC) of isolated Si domains. Our study not only demonstrates the fabrication by AIC of shape- and size-controlled Si monocrystals at the nanoscale but also allows for the prediction of minimal annealing conditions for complete crystallization of such structures. These ultrathin [111]-oriented monocrystals are promising candidates as selected-area epitaxy substrates with both an easy control on the morphology of these structures and a low-temperature fabrication process.
K. Madiomanana, M. Bahri, J.B. Rodriguez, L. Largeau, L. Cerutti, O. Mauguin, A. Castellano, G. Patriarche, and E. Tournié
Elsevier BV
N. Ben Sedrine, X. Lafosse, O. Mauguin, R. Chtourou, and J.C. Harmand
Elsevier BV
A. Ghrib, M. El Kurdi, M. Prost, M. de Kersauson, L. Largeau, O. Mauguin, G. Beaudoin, S. Sauvage, X. Checoury, G. Ndong,et al.
SPIE
The keystone to realize a monolithic integrated source on silicon with germanium is to optimize tensile strain and n-doping. In order to realize an integrated compact source, we demonstrate highly strained n-doped germanium microdisks obtained by two approaches using initially compressed silicon nitride (SiN) deposition. In the first approach, the microdisks are fabricated from relaxed Ge. In a second approach, we use tensile-strained Ge grown on a mismatched buffer layer, thus increasing the global strain in the Ge volume and lowering its gradient. A photoluminescence red-shift up to 450 nm is observed, corresponding to more than 1% biaxial strain.
Silvia Mariani, Alessio Andronico, Olivia Mauguin, Aristide Lemaître, Ivan Favero, Sara Ducci, and Giuseppe Leo
The Optical Society
We report on the design, the fabrication, and the optical characterization of AlGaAs microdisks suspended on a GaAs pedestal, conceived for second-harmonic generation with a pump in the third telecom window. We discuss the results concerning the linear characterization of whispering gallery modes at fundamental and second-harmonic wavelengths, an essential step prior to the investigation of quasi-phase-matched processes in this type of microcavity.