B. Daudin
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View article: Wurtzite vs zinc blende phase selection in GaN nanowires
Wurtzite vs zinc blende phase selection in GaN nanowires Open
Due to the difference between the bandgap value of wurtzite and zincblende GaN variants, the realization of homo-epitaxial wurtzite/zincblende GaN heterostructures has been considered for long as an attractive possibility to grow optoelect…
View article: Optical properties of basal plane stacking faults in AlN nanowires
Optical properties of basal plane stacking faults in AlN nanowires Open
It is shown that depending on growth conditions, cathodoluminescence and photoluminescence spectra of AlN nanowires grown by plasma-assisted molecular beam epitaxy exhibit a peculiar optical signature around 5.85 eV. Several contributions …
View article: Inhomogeneous spatial distribution of non radiative recombination centers in GaN/InGaN nanowire heterostructures studied by cathodoluminescence
Inhomogeneous spatial distribution of non radiative recombination centers in GaN/InGaN nanowire heterostructures studied by cathodoluminescence Open
In order to elucidate the mechanisms responsible for cathodoluminescence intensity variations at the scale of single InGaN/GaN nanowire heterostructures, a methodology is proposed based on a statistical analysis on ensembles of several hun…
View article: Comprehensive Electro-Optical Investigation of a Ga-Doped AlN Nanowire LED for Applications in the UV-C Range
Comprehensive Electro-Optical Investigation of a Ga-Doped AlN Nanowire LED for Applications in the UV-C Range Open
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View article: Ultrathin GaN quantum wells in AlN nanowires for UV-C emission
Ultrathin GaN quantum wells in AlN nanowires for UV-C emission Open
Molecular beam epitaxy growth and optical properties of GaN quantum disks in AlN nanowires were investigated, with the purpose of controlling the emission wavelength of AlN nanowire-based light emitting diodes. Besides GaN quantum disks wi…
View article: Optical properties of Ga-doped AlN nanowires
Optical properties of Ga-doped AlN nanowires Open
We show that intentional Ga doping of AlN nanowires in the 0.01%–0.5% range leads to the spontaneous formation of nanometric carrier localization centers. Accordingly, for single nanowires, we observed a collection of sharp cathodoluminesc…
View article: The role of surface states and point defects on optical properties of InGaN/GaN multi-quantum wells in nanowires grown by molecular beam epitaxy
The role of surface states and point defects on optical properties of InGaN/GaN multi-quantum wells in nanowires grown by molecular beam epitaxy Open
The optical properties of nanowire-based InGaN/GaN multiple quantum wells (MQWs) heterostructures grown by plasma-assisted molecular beam epitaxy are investigated. The beneficial effect of an InGaN underlayer grown below the active region …
View article: DX center formation in highly Si doped AlN nanowires revealed by trap assisted space-charge limited current
DX center formation in highly Si doped AlN nanowires revealed by trap assisted space-charge limited current Open
Electrical properties of silicon doped AlN nanowires grown by plasma assisted molecular beam epitaxy were investigated by means of temperature dependent current–voltage measurements. Following an Ohmic regime for bias lower than 0.1 V, a t…
View article: Nanoscale imaging of dopant incorporation in n-type and p-type GaN nanowires by scanning spreading resistance microscopy
Nanoscale imaging of dopant incorporation in n-type and p-type GaN nanowires by scanning spreading resistance microscopy Open
The realization of practical semiconductor nanowire optoelectronic devices requires controlling their electrical transport properties, which are affected by their large surface/volume ratio value and potentially inhomogeneous electrical do…
View article: Shallow donor and DX state in Si doped AlN nanowires grown by molecular beam epitaxy
Shallow donor and DX state in Si doped AlN nanowires grown by molecular beam epitaxy Open
Si doping of AlN nanowires (NWs) grown by plasma assisted molecular beam epitaxy was investigated with the objective of fabricating efficient AlN based deep ultra-violet light-emitting-diodes. The Si concentration ranged from 1016 to 1.8 ×…
The role of surface diffusion in the growth mechanism of III-nitride nanowires and nanotubes Open
The spontaneous growth of GaN nanowires (NWs) in absence of catalyst is controlled by the Ga flux impinging both directly on the top and on the side walls and diffusing to the top. The presence of diffusion barriers on the top surface and …
Growth of zinc-blende GaN on muscovite mica by molecular beam epitaxy Open
The mechanisms of plasma-assisted molecular beam epitaxial growth of GaN on muscovite mica were investigated. Using a battery of techniques, including scanning and transmission electron microscopy, atomic force microscopy, cathodoluminesce…
Enhanced UV Emission of GaN Nanowires Functionalized by Wider Band Gap Solution-Processed p-MnO Quantum Dots Open
GaN-based UV light-emitting devices suffer from low efficiency. To mitigate this issue, we hybridized GaN nanowires (NWs) grown on Si substrates by plasma-assisted molecular beam epitaxy with solution-processed p-type MnO quantum dots (QDs…
Impact of kinetics on the growth of GaN on graphene by plasma-assisted molecular beam epitaxy Open
The growth of GaN on graphene by molecular beam epitaxy was investigated. The most stable epitaxial relationship, i.e. [00.1]-oriented grains, is obtained at high temperature and N-rich conditions, which match those for nanowire growth. Al…
View article: Mg and In Codoped p-type AlN Nanowires for pn Junction Realization
Mg and In Codoped p-type AlN Nanowires for pn Junction Realization Open
Efficient, mercury-free deep ultraviolet (DUV) light-emitting diodes (LEDs) are becoming a crucial challenge for many applications such as water purification. For decades, the poor p-type doping and difficult current injection of Al-rich A…
View article: Role of Ga Surface Diffusion in the Elongation Mechanism and Optical Properties of Catalyst-Free GaN Nanowires Grown by Molecular Beam Epitaxy
Role of Ga Surface Diffusion in the Elongation Mechanism and Optical Properties of Catalyst-Free GaN Nanowires Grown by Molecular Beam Epitaxy Open
We have shown that both the morphology and elongation mechanism of GaN nanowires homoepitaxially grown by plasma-assisted molecular beam epitaxy (PA-MBE) on a [0001]-oriented GaN nanowire template are strongly affected by the nominal galli…
Vacancy-type defects in GaN self-assembled nanowires probed using monoenergetic positron beam Open
Vacancy-type defects in GaN nanowires (NWs) and the trapping of electrons by the vacancies were studied by positron annihilation. Undoped, Si-, and Mg-doped GaN NWs were grown on Si substrates by plasma-assisted molecular beam epitaxy. The…
View article: Polarity conversion of GaN nanowires grown by plasma-assisted molecular beam epitaxy
Polarity conversion of GaN nanowires grown by plasma-assisted molecular beam epitaxy Open
It is demonstrated that the N-polarity of GaN nanowires (NWs) spontaneously nucleated on Si (111) by molecular beam epitaxy can be reversed by intercalation of an Al- or a Ga-oxynitride thin layer. The polarity change has been assessed by …
Incorporation of Europium into GaN Nanowires by Ion Implantation Open
Rare earth (RE)-doped GaN nanowires (NWs), combining the well-defined and controllable optical emission lines of trivalent RE ions with the high crystalline quality, versatility, and small dimension of the NW host, are promising building b…
Incorporation of Europium into GaN Nanowires by Ion Implantation Open
Rare earth (RE)-doped GaN nanowires (NWs), combining the well-defined and controllable optical emission lines of trivalent RE ions with the high crystalline quality, versatility, and small dimension of the NW host, are promising building b…
Multiple optical centers in Eu-implanted AlN nanowires for solid-state lighting applications Open
A detailed spectroscopic analysis of Eu3+ implanted and annealed AlN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy is presented by using micro-Raman, temperature-dependent steady-state photoluminescence, and time-resolved…
Picometre‐precision atomic structure of inversion domain boundaries in <span>GaN</span> Open
Here, we report on the precise analysis of the atomic structure of inversion domain boundaries (IDBs) in GaN by scanning transmission electron microscopy. IDBs are a common defect in GaN that traps carriers and leads to a slightly modified…
A novel way of measuring lifetime at the nanometer scale using specific fast electron‐matter interactions Open
Charge carrier lifetime is a key parameter for understanding the physics of electronic or optical excitations. For example the excited state can unveil details of environmental influence, specifically the role of non‐radiative transitions.…
View article: Quantification of dopants in nanomaterial by <scp>SEM</scp> / <scp>EDS</scp>
Quantification of dopants in nanomaterial by <span>SEM</span> / <span>EDS</span> Open
It is long known that doping is a key element in the development of modern semiconductor technology for applications in electronic, nano‐electronics, optoelectronics and photonics. Doping allows modifications in the electrical conductivity…
Unraveling the strain state of GaN down to single nanowires Open
GaN nanowires (NWs) grown by molecular beam epitaxy are usually assumed free of strain in spite of different individual luminescence signatures. To ascertain this usual assumption, the c/a of a GaN NW assembly has been characterized using …
Direct assessment of p–n junctions in single GaN nanowires by Kelvin probe force microscopy Open
Making use of Kelvin probe force microscopy, in dark and under ultraviolet illumination, we study the characteristics of p-n junctions formed along the axis of self-organized GaN nanowires (NWs). We map the contact potential difference of …
Direct Measurement of Polarization-Induced Fields in GaN/AlN by Nano-Beam Electron Diffraction Open
The built-in piezoelectric fields in group III-nitrides can act as road blocks on the way to maximizing the efficiency of opto-electronic devices. In order to overcome this limitation, a proper characterization of these fields is necessary…
Phonon–plasmon coupling in Si doped GaN nanowires Open
The vibrational properties of silicon doped GaN nanowires with diameters comprised between 40 and 100 nm are studied by Raman spectroscopy through excitation with two different wavelengths: 532 and 405 nm. Excitation at 532 nm does not all…