A5054248819- GaN-based semiconductor devices and materials
- Electron and X-Ray Spectroscopy Techniques
- ZnO doping and properties
- Ga2O3 and related materials
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- X-ray Spectroscopy and Fluorescence Analysis
- Thin-Film Transistor Technologies
- Electrocatalysts for Energy Conversion
- Chalcogenide Semiconductor Thin Films
- Advanced Electron Microscopy Techniques and Applications
- Semiconductor Lasers and Optical Devices
- Radioactivity and Radon Measurements
- Astrophysical Phenomena and Observations
- Advanced Semiconductor Detectors and Materials
- High-pressure geophysics and materials
- Silicon Carbide Semiconductor Technologies
- Fuel Cells and Related Materials
- Advancements in Battery Materials
- Photocathodes and Microchannel Plates
- Astrophysics and Star Formation Studies
- Electronic and Structural Properties of Oxides
- Nuclear Physics and Applications
- Advanced battery technologies research
European Synchrotron Radiation Facility
2015-2021
Université Grenoble Alpes
2011-2014
Centre National de la Recherche Scientifique
2011-2014
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2011-2014
CEA LETI
2011-2014
Institut Néel
2014
CEA Grenoble
2011-2013
Institut Nanosciences et Cryogénie
2011-2013
Institut polytechnique de Grenoble
2011-2013
Université Joseph Fourier
2011
Within the framework of ESRF Phase I Upgrade Programme, a new state-of-the-art synchrotron beamline ID16B has been recently developed for hard X-ray nano-analysis. The construction was driven by research areas with major scientific and societal impact such as nanotechnology, earth environmental sciences, bio-medical research. Based on canted undulator source, this long provides nanobeams optimized mainly spectroscopic applications, including combination fluorescence, diffraction, excited...
Nonpolar InGaN/GaN multiple quantum wells (MQWs) grown on the {11̅00} sidewalls of c-axis GaN wires have been by organometallic vapor phase epitaxy c-sapphire substrates. The structural properties single are studied in detail scanning transmission electron microscopy and a more original way secondary ion mass spectroscopy to quantify defects, thickness (1–8 nm) In-composition (∼16%). core–shell MQW light emission characteristics (390–420 nm at 5 K) were investigated cathodo-...
We present a letter on single-wire photodetectors based radial n-i-n multiquantum well (QW) junctions. The devices are realized from GaN wires grown by catalyst-free metalorganic vapor phase epitaxy coated at their top five nonpolar In0.16Ga0.84N/GaN undoped QWs, and sensitive to light with energy E>2.6 eV. Their photoconductive gain is as high 2×103. scanning photocurrent microscopy maps evidence that the detector response localized extremity containing QWs for both below (at λ=488...
Single-wire light-emitting diodes based on radial p–i–n multi quantum well (QW) junctions have been realized from GaN wires grown by catalyst-free metal organic vapor phase epitaxy. The InxGa1-xN/GaN undoped QW system is coated over both the nonpolar lateral sidewalls and polar upper surface. Cathodo- electroluminescence (EL) experiments provide evidence that QWs emit in visible spectral range at systematically lower energy than QWs. EL of or can be selectively activated varying sample...
A report is presented on the fabrication of light emitting diodes (LEDs) based GaN core/shell wires conductive substrates by metal organic vapour phase epitaxy. Catalyst-free GaN-based are grown spontaneously 2-inch n-doped silicon without any thick buffer layer. The LED wire heterostructure consists an n-type GaN:Si core covered radially five InGaN/GaN quantum wells and a p-type GaN:Mg shell. Macroscopic devices that integrate around 106 wire-LEDs have been obtained thanks to simple, direct...
Unrivaled XANES imaging resolution of <100 nm, and XBIC conclusively identify the active area a nanowire device.
Abstract Nitrogen-doped reduced graphene oxide is successfully synthesized and functionalized with hydroxylated copper ions via one-pot microwave-assisted route. The presence of cationic Cu coordinated to the layer fully elucidated through a set experimental characterizations theoretical calculations. Thanks these hydroxyl-coordinated 2+ active sites, proposed material shows good electrocatalytic performance for oxygen reduction reaction, as evidenced by an electron transfer number almost 4...
GaN wires are grown on a Si (111) substrate by metal organic vapour-phase epitaxy thin deposited AlN blanket and through SiNx layer formed spontaneously at the AlN/Si interface. N-doped used as templates for growth of core-shell InGaN/GaN multiple quantum wells coated p-doped shell. Standing single-wire heterostructures connected using metallic tip backside contact, electroluminescence room temperature forward bias is demonstrated 420 nm. This result points out feasibility lower cost...
The properties of semiconductors can be controlled using doping, making it essential for electronic and optoelectronic devices. However, with shrinking device sizes becomes increasingly difficult to quantify doping sufficient sensitivity spatial resolution. Here, we demonstrate how X-ray fluorescence mapping a nanofocused beam, nano-XRF, Zn within in situ doped III–V nanowires, by large area detectors high-efficiency focusing optics. resolution is defined the focus size 50 nm. detection...
The lack of low-cost, durable and highly efficient electrocatalysts to perform oxygen reduction reaction (ORR) still represents a significant challenge for the development fuel cells cathodes. Recently, Pt-free metalloporphyrins supported on N-doped reduced graphene oxide (N-rGO) have been proposed as innovative ORR catalysts characterized by notable stability superior performance. In this paper, we propose fast green microwave-assisted method synthetize manganese-nitrogen co-doped rGO,...
Here it is demonstrated how nanofocused X-ray beam induced current (XBIC) can be used to quantitatively map the spatially dependent carrier collection probability within nanostructured solar cells. The photocurrent generated by a 50 nm-diameter was measured as function of position, bias and flux in single p–i–n doped solar-cell nanowires. signal gathered mostly from middle segment decays exponentially toward p- n-segments, with characteristic decay length that varies between nm 750 depending...
Well-ordered and vertically aligned InN nanorods with high aspect ratios are synthesized by hydride vapor phase epitaxy (HVPE) using the selective area growth (SAG) approach.
We present two complementary approaches to investigate the In content in GaAs/(In,Ga)As/(GaAs) core-shell-(shell) nanowire (NW) heterostructures using synchrotron radiation. The key advantage of our methodology is that NWs are characterized their as-grown configuration, i.e., perpendicularly standing on a substrate. First, we determine mean (In,Ga)As shell by high-resolution x-ray diffraction (XRD) from NW ensembles. particular, disentangle influence and thickness XRD measuring analyzing...
We demonstrate x-ray absorption fine structure spectroscopy (XAFS) detected by beam induced current (XBIC) in single n + -i-n doped nanowire devices. Spatial scans with the 65 nm diameter show a peak of XBIC signal middle segment nanowire. The and fluorescence signals were simultaneously as function excitation energy near Ga K edge at 10.37 keV. spectra similar oscillations around edge, which shows that is limited primary absorption. Our results reveal feasibility detection mode for XAFS...
Protoplanetary disks, interstellar clouds, and active galactic nuclei, contain X-ray dominated regions. X-rays interact with the dust gas present in such environments. While a few laboratory irradiation experiments have been performed on ices, bare cosmic analogs scarce up to now. Our goal is study effects of hard via in-situ diffraction. By using synchrotron nanobeam, we seek simulate cumulative exposure grains during their lifetime these astrophysical environments, provide an upper limit...
A helium mini-cryostat has been developed for the hard X-ray nanoprobe ID16B of European Synchrotron to collect excited optical luminescence and fluorescence at low temperature (<10 K). The specifically designed fit within strong space restrictions high-demanding mechanical constraints imposed by beamline provide vibration-free operation maximal thermal stability. This paper reports detailed design, architecture technical requirements mini-cryostat, presents first experimental data...
Thin-wall tubes composed of nitride semiconductors (III-N compounds) based on GaN/InAlN multiple quantum wells (MQWs) are fabricated by metal-organic vapor-phase epitaxy in a simple and full III-N approach. The synthesis such MQW-tubes is the growth N-polar c-axis vertical GaN wires surrounded core-shell MQW heterostructure followed situ selective etching using controlled H2/NH3 annealing at 1010 °C to remove inner wire part. After this process, well-defined MQW-based having nonpolar m-plane...
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Time-resolved cathodoluminescence is a key tool with high temporal and spatial resolution. However, optical spectroscopic information can be also extracted using synchrotron pulses in hard X-ray nanoprobe, exploiting phenomenon called excited luminescence. Here, 20 ps time resolution 80 nm lateral resolution, we applied this time-resolved microscopy technique to individual core-shell InGaN/GaN multiple quantum well heterostructures deposited on GaN wires. Our findings suggest that the...
With a long experience in optoelectronics, CEA-LETI has focused on Light Emitting Diode (LED) lighting since 2006. Today, all the technical challenges implementation of GaN LED based solid state (SSL) are addressed at who is now an RandD player throughout entire value chain lighting. The SSL Line first deals with simulation active structures and devices. Then growth particular 2D 200 mm silicon substrates. Then, technological steps developed for fabrication dies innovative architectures. For...
An abstract is not available for this content so a preview has been provided. As you have access to content, full PDF via the ‘Save PDF’ action button.