A5069938845- Spectroscopy and Laser Applications
- ZnO doping and properties
- Gas Sensing Nanomaterials and Sensors
- Atmospheric Ozone and Climate
- Electronic and Structural Properties of Oxides
- Semiconductor Quantum Structures and Devices
- Terahertz technology and applications
- Advanced Materials Characterization Techniques
- Photonic Crystals and Applications
- Plasmonic and Surface Plasmon Research
- Metamaterials and Metasurfaces Applications
- Diamond and Carbon-based Materials Research
- Force Microscopy Techniques and Applications
- Quantum Dots Synthesis And Properties
- GaN-based semiconductor devices and materials
- Surface Roughness and Optical Measurements
- Solid State Laser Technologies
- Magnetic and transport properties of perovskites and related materials
- Acoustic Wave Resonator Technologies
- Perovskite Materials and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Strong Light-Matter Interactions
- Copper-based nanomaterials and applications
- Random lasers and scattering media
- Laser Design and Applications
Université Côte d'Azur
2017-2022
Centre National de la Recherche Scientifique
2017-2022
Institut de Biologie Valrose
2022
Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications
2017-2019
Observatoire de la Côte d’Azur
2018
We have developed a method to grow and characterize the state of art non-polar ZnO/(Zn,Mg)O multi-quantum wells on m-plane ZnO substrates as prerequisite for applications based intersubband transitions. The epilayer interfaces exhibit low roughness, layer thickness remains constant within one monolayer in these heterostructures. optical properties been studied UV IR domains by means photoluminescence absorption experiments, respectively. In UV, is very well described an excitonic transition,...
This paper reports on the demonstration of quantum cascade detectors (QCDs) based ZnO/ZnMgO wells (QWs) grown by molecular beam epitaxy an m-plane ZnO substrate. The TM-polarized intersubband absorption is peaked at a 3 μm wavelength. sample has been processed in form square mesas with sizes ranging from 10 × μm2 up to 100 μm2. I-V characteristics reveal that 86% 260 devices are operational and surface leakage current negligible room temperature, which not case 77 K. photocurrent...
The ZnO-based heterostructures are predicted to be promising candidates for optoelectronic devices in the infrared and terahertz (THz) spectral domains owing their intrinsic material properties. Specifically, large ZnO LO-phonon energy reduces thermally activated scattering, which is greatly improve temperature performance of THz quantum cascade lasers. However, date, no experimental observation intersubband emission from has been reported. Here, we report electroluminescence ZnO/MgxZn1–xO...
Unexpected light propagation effects, such as negative refraction, have been reported in artificial media. Leveraging on the intersubband resonances heterostructured semiconductors, we show that all possible optical regimes, ranging from classical dieletric and metal to hyperbolic metamaterial types 1 2, can be achieved. As a demonstration, prove refraction effect occur at designed frequency by controlling electronic quantum confinement.
Highly doped multiple quantum wells (MQWs) are significant for infrared optoelectronics, plasmonics, and the physics of strong light-matter coupling. The authors reveal a multisubband plasmon (MSP) that arises from couplings among several intersubband transitions in (Mg,Zn)O/ZnO MQWs, due to outstandingly dense two-dimensional electron gas. Here MSP energy is up three times constituent transitions, illustrating potential this system optoelectronic applications infrared, which could be...
Intersubband transitions in ZnO-based materials are predicted to be a promising basis for infrared and terahertz optoelectronic devices, particularly quantum cascade lasers. Utilizing nonpolar ZnO substrate optimizing growth conditions, the authors observe strong coupling between asymmetric ZnO/Mg${}_{x}$Zn${}_{1\ensuremath{-}x}$O wells. due high doping level heterostructures leads formation of multisubband plasmons. The results an important step toward realization ultrafast ZnO/MgxZn1-xO...
Atom Probe Tomography (APT) is a microscopy technique allowing for the 3D reconstruction of chemical composition nanoscale needle-shaped sample with precision close to atomic scale. The photonic atom probe (PAP) an evolution APT featuring in situ and operando detection photoluminescence signal. optical signatures light-emitting centers can be correlated structural information obtained by analysis evaporated ions. It becomes thus possible discriminate interpret spectral different light...
The possibility of measuring in situ operando photoluminescence spectroscopy within a photonic atom probe allows for the real-time study mechanical stress state field emitter either statically, as function field-induced tensile stress, or dynamically, result evolution shape upon its evaporation. Dynamic results from relaxation strain induced by lattice mismatch and propagation apex, while morphology changes. Optomechanical information can be interpreted through three-dimensional atomic scale...
The electrical and optical properties of m-plane Ga-doped ZnMgO alloys are analyzed by capacitance-voltage profiling, Hall effect, IR reflectance UV-VIS absorption spectroscopies, spanning more than four orders magnitude in electron concentration. Mg contents up to 50% achieved while maintaining the wurtzite phase, with a measured band-edge energy 4.41 eV. Despite deterioration incorporation, high concentrations (∼4.4×1019cm−3) for 35%, revealing doping efficiencies close 100%. potential...
Optoelectronic devices based on intersubband transitions (ISBT) typically require surface texturing after growth, to overcome the selection rules for polarization and operate under normally incident light. The authors demonstrate that $m$-plane ZnO/(Mg,Zn)O multiple quantum wells (QWs) self-assemble in a geometry allows absorption at normal incidence, depending state of light with respect $c$ axis. These QWs behave as self-assembled metamaterial, building block polarization-sensitive...
Intersubband (ISB) polarons result from the interaction of an ISB transition and longitudinal optical (LO) phonons in a semiconductor quantum well (QW). Their observation requires very dense two dimensional electron gas (2DEG) QW polar or highly ionic semiconductor. Here we show that ZnO/MgZnO QWs strength such coupling can be as high 1.5 times LO-phonon frequency due to 2DEG achieved large difference between static high-frequency dielectric constants ZnO. The polaron is observed optically...
A method based on infrared reflectance spectroscopy is presented by which the Mg content in ZnO/(Zn,Mg)O multiple quantum wells with very thin barriers can be determined. The relies observation of interface phonon-polaritons appear as sharp dips p-polarized spectra at oblique incidence near longitudinal optical (LO)-phonon frequencies both QW and barrier materials. By fitting to a dielectric function model, LO phonon frequency (Zn,Mg)O layers depends content. Comparing calibration via...
In this work we show the potential of ZnO/ZnMgO material system for intersubband (ISB)-based devices. This family alloys presents a unique set properties that makes it highly attractive THz emission as well strong coupling regimes: has very large longitudinal optical phonon energy 72 meV, can be doped up to ~10<sup>21</sup> cm<sup>-3</sup>, is ionic with difference between static and high frequency dielectric constants, grown homoepitaxially on native substrates low defect densities. The...
We studied polarization-resolved photoluminescence originating from a ZnO-(Mg,Zn)O quantum well heterostucture embedded within an atom probe tip, i.e. nanoscale needle-shaped sample with apex radius of several tens nm, prepared by focused ion beam. The study was carried out photonic before the analysis sample. This setup allows for polarization emitted tip and its orientation around axis. While bulk ZnO (Mg,Zn)O alloy is strongly polarized along axis, coinciding crystal [1-100] ZnO/(Mg,Zn)O...
We present a systematic investigation of intersubband transitions in nonintentionally doped $m\text{\ensuremath{-}}\mathrm{plane}$ ZnO/ZnMgO quantum wells (QWs). The is performed using photoinduced absorption spectroscopy at room temperature under optical pumping by UV laser to generate electron-hole pairs. All samples exhibit TM-polarized intersubbandlike resonances. However, the peak transition energy largely blueshifted (>100 meV) with expectations from electronic confinement...
Quantum cascade (QC) lasers opens new prospects for powerful sources operating at THz frequencies. Up to now the best QC are based on intersubband emission in GaAs/AlGaAs quantum well (QW) heterostructures. The maximum temperature is 200 K, which too low wide-spread applications. This due rather LO-phonon energy (36 meV) of GaAs-based materials. Indeed, thermal activation allows non-radiative path through electron-phonon interaction destroys population inversion. Wide band gap materials such...
The development of Zinc Oxide (ZnO)-based applications have been strongly limited due to the lack reproducible p-type doping. Here we present novel opportunities in field unipolar oxide wide band gap semiconductors. First developed growth nonpolar ZnO/ZnMgO multiple quantum wells (MQWs) and then demonstrate that structural optical properties MQWs are reaching required level for intersubband devices terms defects, surface interface roughness We will show discuss most recent results as,...
Although ZnO and its related heterostructures are really attractive for their potential application in optoelectronics, developments have been limited by the p-type doping issue. Here, we will show why properties also very unipolar structures, only dealing with electrons, how material quality has improved to reach these devices requirements. First, benefit of homoepitaxy through improvement is presented. We that molecular beam epitaxy allows getting defect density, surface roughness,...
We report on the first demonstration of quantum cascade detectors based ZnO/ZnMgO wells grown by molecular beam epitaxy an m-plane ZnO substrate. The sample is processed in form square mesas with special attention paid to passivation side facets. Photocurrent spectroscopy reveals a resonance at 2.8 μm wavelength slightly blue-shifted respect intersubband absorption peak 3 wavelength. photocurrent persists up room temperature. responsivity amounts 0.15 mA/W under irradiation Brewster's angle...
We theoretically and experimentally demonstrate negative refraction in a semiconductorsystem operating at mid-infrared wavelengths. Such effect is generic realized by electrons quantum confinement wells, acting as an adjustable resonance. © 2019 The Author(s)
We theoretically and experimentally demonstrate negative refraction in a semiconductor system operating at mid-infrared wavelengths. Such effect is generic realized by electrons quantum confinement wells, acting as an adjustable resonance.
Recently Zinc Oxide has received a renewed attention for the realization of intersubband devices such as quantum cascade lasers (QCLs). Indeed this material is predicted to be able tackle main limitation current terahertz (THz) QCLs: limited operation temperature. We report observation electronic coupling within ZnO/(Zn, Mg)O asymmetric wells (QWs), first step towards goal. Samples were grown by molecular beam epitaxy (MBE) with surfaces down 0.4 nm. X-ray reflectivity (XRR) was used...