Publications de Benjamin Dwir | EPFL Graph Search

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Remote coupling between quantum emitters is of great importance for constructing quantum networks. Conventionally, this can be achieved via photon exchange by incorporating the quantum emitters in a waveguide or a large cavity. However, such photonic struc ...

We demonstrate the self-formation of hexagonal nanotemplates on GaAs (111)B substrates patterned with arrays of inverted tetrahedral pyramids during metal-organic vapor phase epitaxy and its role in producing high-symmetry, site-controlled quantum dots (QD ...

A compact platform to integrate emitters in a cavity-like support is to embed quantum dots (QDs) in a photonic crystal (PhC) structure, making them promising candidates for integrated quantum photonic circuits. The emission properties of QDs can be modifie ...

Radiation properties of a pointlike source of light, such as a molecule or a semiconductor quantum dot, can be tailored by modifying its photonic environment. This phenomenon lies at the core of cavity quantum electrodynamics (CQED). Quantum dots in photon ...

InGaAs/GaAs quantum dots (QDs) embedded in a GaAs substrate are very useful photon sources, including single and entangled photons, due to their unperturbed environment. Contrary to self-formed QDs, those grown in pyramidal pits can be well controlled in p ...

Focused electron beam induced depositions of nickel-containing materials obtained by using bis(methylcyclopentadienyl)nickel(II) Ni(C5H4CH3)(2) and tetrakis(trifluorophosphine)nickel(0) Ni(PF3)(4) as precursors, were compared in terms of chemical composition and electrical resistivity. Ni(PF3)(4) decomposed into higher Ni content materials than that obtained with Ni(C5H4CH3)(2) (typically 40 and 10 at. %, respectively). Attempts of increasing the Ni content by injecting controlled flows of molecular oxygen

GaInAsN quantum dots (QDs) were grown in inverted pyramids on a patterned (111) B GaAs surface. Incorporation of N in the active structure is attested to by a significant (similar to 80 meV) redshift of the photoluminescence spectrum of the QDs. Influence of the capillarity effect on the N incorporation is evidenced by comparing the redshift in the QD emission to that of its quantum wire (QWR) barriers. The significant increase in the inhomogeneous broadening of the InGaAsN QD arrays as compared to similar

Negatively and positively charged excitons are identified in the spatially resolved photoluminescence spectra of quantum wires. We demonstrate that charged excitons are weakly localized in disordered quantum wires. As a consequence, the enhancement of the ...

The properties of single site-controlled InGaAsN quantum wires (QWRs)-both untreated and irradiated with atomic hydrogen-are probed by micro-magnetophotoluminescence spectroscopy. The strong anisotropy of the diamagnetic shift measured for different orient ...

We demonstrate the ability to precisely control the deposition of a defined number of carbon nanotubes (CNTs) from solution onto microfabricated electrodes using dielectrophoresis. The solvation shelf around the CNTs, exhibiting a high dielectric constant ...

The formation mechanisms, structure and optoelectronic properties of Ga(In)As/(Al)GaAs quantum dot (QD) heterostructures grown by organometallic chemical vapor deposition on patterned (111)B GaAs substrates are reviewed. With this approach, it is possible to prepare high-quality semiconductor QDs whose position on a substrate is precisely controlled via a pre-growth photolithography step. The dots are formed at the center of an inverted, tetrahedral pyramid and are surrounded by distinct, low-dimensional ba

We report on the effects of optical disorder on breaking the symmetry of the cavity modes of H-3 photonic crystal cavities incorporating site-controlled pyramidal quantum dots (QDs) as the internal light source. The high in-plane symmetry of the polarizati ...

investigate the use of MOVPE-grown ordered nanostructures on non-planar substrates for quantum nano-photonics and quantum electrodynamics-based applications. The mastering of surface adatom fluxes on patterned GaAs substrates allows for forming nanostrucutres confining well-defined charge carrier states. An example given is the formation of quantum dot (QD) molecules tunneled-coupled by quantum wires (QWRs), in which both electron and hole states are hybridized. In addition, it is shown that the high degree

We have measured the temperature dependence of the conductance of long V-groove quantum wires fabricated using GaAs/AlGaAs heterostructures, in a wide temperature range (200 mK < T < 4.2 K). We find that for our quantum wires the Fermi velocity can be as l ...

We report on the fabrication of two-dimensional arrays of nano-optical apertures in gold layers by electron beam lithography (EBL) on a transparent glass substrate. 30 x 30 μ m(2) large arrays of high aspect ratio sub-wavelength cylinders (400 nm diameter ...

Optoelectronic properties of site-controlled AlGaAs/GaAs quasi-one-dimensional structures are investigated. Controllable linear variation of the band gap along the vertical axis of the quantum wire, symmetrical with respect to its center, results in a set ...

Strong optical confinement implemented with 2D photonic-crystal (PhC) microcavities provides a powerful tool for controlling the features of light-matter interaction. Combined with nanostructures such as quantum wells, quantum wires (QVTRs) or quantum dots, the PhC cavities - efficiently controlling spontaneous emission [1] are envisaged to bring superior semiconductor-laser performance [2], which could be exploited for applications in low-power-consumption integrated optoelectronics. Furthermore, inter-cav

We report coupled VCSEL arrays, emitting at 1.3μm wavelength, in which both the optical gain/loss and refractive index distributions were defined on different vertical layers. The arrays were electrically pumped through a patterned tunnel junction, whereas the array pixels were realized by intra-cavity patterning using sub-wavelength air gaps. Stable oscillations in coupled modes were evidenced for 2x2 array structures, from threshold current up to thermal roll-over, using spectrally resolved field pattern

Intraband photocurrent spectroscopy of site-controlled pyramidal quantum dots by inserting them into the intrinsic region of n-i-n like quantum dot infrared photodetector structure is reported. The photovoltaic response is observed in the mid-infrared regi ...

A novel technique for tuning the strength of quantum confinement in site-controlled semiconductor quantum dots (QDs) is introduced and investigated theoretically and experimentally. The method makes use of controlled local growth rates during metalorganic ...

Benjamin Dwir

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Remote excitation between quantum emitters mediated by an optical Fano resonance

Self-formation of hexagonal nanotemplates for growth of pyramidal quantum dots by metalorganic vapor phase epitaxy on patterned substrates

Spatial quantum-interference landscapes of multi-site-controlled quantum dots coupled to extended photonic cavity modes

Mode Interference Effect in Optical Emission of Quantum Dots in Photonic Crystal Cavities

Enhanced photon emission from site- and energy-controlled InGaAs/GaAs quantum dots coupled to GaAs nanowires

Focused electron beam induced deposition of nickel

Dilute-nitride GaInAsN/GaAs site-controlled pyramidal quantum dots

Enhancement of the binding energy of charged excitons in disordered quantum wires

Magneto-optical properties of single site-controlled InGaAsN quantum wires grown on prepatterned GaAs substrates

Controlled Positioning of Carbon Nanotubes by Dielectrophoresis : Insights into the Solvent and Substrat Role

Site- and energy-controlled pyramidal quantum dot heterostructures

Polarization properties and disorder effects in H-3 photonic crystal cavities incorporating site-controlled, high-symmetry quantum dot arrays

Active Semiconductor Nanophotonics based on Deterministic Quantum Wire and Dot Systems

Experimental evidence for Luttinger liquid behavior in sufficiently long GaAs V-groove quantum wires

Fabrication of arrays of sub-wavelength nano-apertures in an optically thick gold layer on glass slides for optical studies

Multiexciton dynamics in tailored band-gap quasi-one-dimensional systems

Coupled Photonic-Crystal Cavities and Quantum-Wire Microlasers

Intra-cavity patterning for mode control in 1.3μm coupled VCSEL arrays

Photocurrent spectroscopy of site-controlled pyramidal quantum dots

Mechanisms of Quantum Dot Energy Engineering by Metalorganic Vapor Phase Epitaxy on Patterned Nonplanar Substrates