A5016613191- solar cell performance optimization
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and interfaces
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advanced Semiconductor Detectors and Materials
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Quantum Dots Synthesis And Properties
- GaN-based semiconductor devices and materials
- Semiconductor Lasers and Optical Devices
- Nonlinear Photonic Systems
- Graphene research and applications
- Thin-Film Transistor Technologies
- Terahertz technology and applications
- Solar Thermal and Photovoltaic Systems
- Photovoltaic System Optimization Techniques
- Laser-Matter Interactions and Applications
- Photonic Crystals and Applications
- Advancements in Semiconductor Devices and Circuit Design
Université de Sherbrooke
2014-2023
Centre de Nanosciences et de Nanotechnologies
2007-2022
Laboratoire Nanotechnologies et Nanosystèmes
2015-2022
Centre for Interdisciplinary Research in Rehabilitation
2022
Regroupement Québécois sur les Matériaux de Pointe
2015
Cambridge University Press
2011
New York University Press
2011
Universitat de Lleida
2011
Laboratoire Procédés, Matériaux et Energie Solaire
2011
Centre National de la Recherche Scientifique
2011
Optical to electrical power converting semiconductor devices were achieved with breakthrough performance by designing a Vertical Epitaxial Heterostructure Architecture. The are featuring modeled and measured conversion efficiencies greater than 65%. ultrahigh obtained monolithically integrating several thin GaAs photovoltaic junctions tailored submicron absorption thicknesses grown in single crystal epitaxy. heterostructures that engineered number N of such ultrathin yielded an optimal...
Photovoltaic power converting III–V semiconductor devices based on the Vertical Epitaxial HeteroStructure Architecture (VEHSA) design have been achieved with up to 20 thin p/n junctions (PT20). Open circuit photovoltages in excess of 23 V are measured for a continuous wave monochromatic optical input ∼1 W tuned 750 nm–875 nm wavelength range. Conversion efficiencies greater than 60% demonstrated when PT20 near peak their spectral response. Noticeably, structure is implemented its narrowest...
Abstract The monolithic integration of III-V compound semiconductor devices with silicon presents physical and technological challenges, linked to the creation defects during deposition process. Herein, a new defect elimination strategy in highly mismatched heteroepitaxy is demonstrated achieve ultra-low dislocation density, epi-ready Ge/Si virtual substrate on wafer scale, using scalable Dislocations are eliminated from epilayer through dislocation-selective electrochemical deep etching...
Abstract Four tunnel junction (TJ) designs for multijunction (MJ) solar cells under high concentration are studied to determine the peak tunnelling current and resistance change as a function of doping concentration. These four TJ are: AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP AlGaAs/GaAs. Time‐dependent time‐average methods used experimentally characterize entire current–voltage profile mesa structures. Experimentally calibrated numerical models minimum required each design operate within MJ...
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.
Semiconductor nanowaveguides are the key structure for light-guiding nanophotonics applications. Efficient guiding and confinement of single-mode light in these waveguides require high aspect ratio geometries. In conditions, sidewall verticality becomes crucial. We fabricated such structures using a top-down process combining electron beam lithography inductively coupled plasma (ICP) etching hard masks GaAs/AlGaAs semiconductors with Al concentrations varying from 0 to 100%. The was...
The morphology of electrochemically formed mesoporous Ge double-layer and its transformations during ultra-high-vacuum annealing at 600–700 °C are investigated by scanning electron microscopy. It was found that the transformation occurs via mass transport constant volume. process transforms pores into faceted spherical voids. These findings determine optimal conditions for a useful structure, which consists 1.8 μm thick monocrystalline film with buried lateral cavities allowing subsequent...
We report modal phase matched (MPM) second harmonic generation (SHG) in high-index contrast AlGaAs sub-micron ridge waveguides, by way of sub-mW continuous wave powers at telecommunication wavelengths.We achieve an experimental normalized conversion efficiency ~14%/W/cm 2 , obtained through a careful subwavelength design supporting both the matching requirement and significant overlap efficiency.Furthermore, weak anomalous dispersion, robust fabrication technology possible geometrical...
We have performed a detailed characterization study of electrochemically etched p-type GaAs in hydrofluoric acid-based electrolyte. The samples were investigated and characterized through cathodoluminescence (CL), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDX), photoelectron (XPS). It was found that after electrochemical etching, the porous layer showed major decrease CL intensity change chemical composition crystalline phase. Contrary to previous reports on p-GaAs...
The design of antireflection coating (ARC) for multijunction solar cells is challenging due to the broadband absorption and need current matching each subcell. Silicon nitride, which deposited by plasma-enhanced chemical vapor deposition (PECVD) using standard conditions, widely used in silicon wafer cell industry but typically suffers from short-wavelength range. We propose use nitride low-frequency PECVD (LFSiN) optimized high refractive index low optical as a part ARC III–V/Ge...
Photon‐recycling effects are studied experimentally in photovoltaic power converting III–V semiconductor devices designed with the vertical epitaxial heterostructure architecture (VEHSA). The responsivity of VEHSA structures multiple thin GaAs n/p junctions is measured for various optical input powers and different wavelength detuning values respect to peak spectral response. While excitation decreases external quantum efficiency at low powers, this study demonstrates that high intensities,...
Abstract A perfectly compliant substrate would allow the monolithic integration of high-quality semiconductor materials such as Ge and III-V on Silicon (Si) substrate, enabling novel functionalities well-established low-cost Si technology platform. Here, we demonstrate a allowing defect-free epitaxial growth lattice mismatched materials. The method is based deep patterning to form micrometer-scale pillars subsequent electrochemical porosification. investigation crystalline quality by X-ray...
In principle, the upper efficiency limit of any solar cell technology can be determined using detailed-balance formalism. However, “real” cells show efficiencies which are always below this theoretical value due to several limiting mechanisms. We study ability a architecture approach its own limit, novel index introduced in work, and amplitude with different mechanisms affect is scrutinized as function electronic gap illumination level submitted. The implications for future generations...
The high-efficiency conversion of photonic power into electrical is broad-range applicability to many industries due its isolation from the surrounding environment and immunity electromagnetic interference which affects performance reliability sensitive electronics. A converter, or phototransducer, can absorb several watts infrared laser transmitted through a multimode fiber convert this for remote use. To useful voltage, we have designed, simulated, fabricated photovoltaic phototransducer...
In this letter, we present an effective GaN surface passivation process, which was developed by optimizing the chemical pretreatment prior to PECVD- SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> deposition. It is demonstrated that electronic properties of GaN/SiO interface are drastically influenced preparation conditions. Among used chemicals, found KOH/HCl leads best quality. MOS capacitors fabricated using have shown a near...
We have experimentally demonstrated broadband tuneable four-wave mixing in AlGaAs nanowires with the widths ranging between 400 and 650 nm lengths from 0 to 2 mm. performed a detailed experimental study of parameters influencing FWM performance these devices (experimental conditions nanowire dimensions). The maximum signal-to-idler conversion range was 100 nm, limited by tuning pump source. efficiency, defined as ratio output idler power signal power, -38 dB. In support our explanation...
A novel approach to the design of multijunction solar cells on silicon substrates for 1-sun applications is described. Models device simulation, including porous layers, are presented. bottom subcell formed by diffusion dopants into a wafer. The top wafer porosified create compliant layer, and III-V buffer layer then grown epitaxially, followed middle subcells. Because resistivity material, these designs best suited high-efficiency applications. Numerical simulations cell that incorporates...
We have studied theoretically and experimentally the properties of optical surface modes at hetero-interface between two meta-materials. These meta-materials consisted 1D AlGaAs waveguide arrays with different band structures.
We experimentally study the nonlinear scattering by local photonic structures embedded in continuous Kerr media and demonstrate trapping guiding resonant transmission antiguiding structures. An intuitive physical picture is presented verified simulations.
The recent theoretical predictions and experimental observations of discrete surface solitons propagating along the interface between a one- or two-dimensional continuous medium waveguide array are reviewed. These were found in second order (periodically poled lithium niobate) third nonlinear media, including AlGaAs, photorefractive media glass, respectively.
A multiple-energy, high fluence, MeV Fe ion implantation process was applied at 83 K to heavily damage a low band gap (0.79 eV) epitaxial InGaAsP layer. Optimal rapid thermal annealing conditions were found and produced fast photoconductor with resistivity (up 2500 Ωcm) Hall mobility around 400 cm2V−1s−1. Short photocarrier trapping times (0.3 ps – 3 ps) observed via transient differential reflectivity measurements. Furthermore, photoconductive terahertz devices coplanar electrodes...
We propose an original thermal analytical model aiming to predict the practical limits of passive cooling systems for high concentration photovoltaic modules. The is described and validated by comparison with a commercial 3D finite element model. limiting performances flat plate in natural convection are then derived discussed.