Publications by Alok Rudra | EPFL Graph Search

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We describe the fabrication, epitaxial growth and photoluminescence (PL) spectra of systems of site-controlled pyramidal quantum dots (QDs) integrated with photonic crystal (PhC) membrane cavities. The spectra of the individual QDs are characterized by sca ...

The authors present low voltage barrier p-InP/p-GaAs junctions obtained by localised fusion which facilitates a better evacuation of absorbed gases and native oxides from the fused interface. Using this approach InGaAs/lnGaAsP/InP edge emitting lasers fused to p-GaAs were realised for the first time, showing better parameters than as-grown diodes. The presented results prove that localised fusion is a suitable tool for achieving additional lateral current confinement, which may be important for a wide varie

A systematic and simple theoretical approach is proposed to analyze true degeneracies and polarized decay patterns of exciton complexes in semiconductor quantum dots. The results provide reliable spectral signatures for efficient symmetry characterization, ...

We have studied the effect of growth interruptions on 2 monolayer thick InAs/InP strained quantum wells (QWS) grown by chemical beam epitaxy. The main feature is the formation of up to 8 monolayer thick InAs islands during As, annealing of the QW. Their formation is characterized by a two- to three-dimensional transition of the reflection high energy electron diffraction (RHEED) pattern and by multiple-line photoluminescence spectra. This interpretation of the data is confirmed by transmission electron micr

We demonstrate several integrated photonics structures incorporating site-controlled quantum dots and photonic crystal cavities with tailored mode structures. Optimal designs for single photon extraction, routing and switching are presented and discussed. ...

We outline the growth mechanismand shape evolution of GaAsnanoridges by selective area MOVPE with three well-identified, distinctstages of growth. ...

We have studied the effect of growth interruptions on 2-monolayers-thick InAs/InP strained quantum wells (QW) grown by chemical beam epitaxy. The main feature is the formation of up to 8-monolayers-thick InAs islands during As2 annealing of the QW. Their formation is characterized by a two to three dimensional transition of the reflection high-energy electron diffraction pattern and multiple-lines photoluminescence spectra. An increase of a short range roughness at the InP-InAs interface due to As2 annealin

Quasi-one-dimensional AlGaAs quantum wires (QWRs) with parabolic heterostructure profiles along their axis were fabricated using metallorganic vapor phase epitaxy (MOVPE) On patterned (111)B GaAs substrates. Tailoring of the confined electronic states via ...

Control on the degree of valence band mixing is experimentally achieved in the particular GaAs/AlGaAs quantum Dot-in-Dot (DiD) structure. The effect is reflected by the tunable polarization of the emitted photons.

Deterministic integration of site-controlled InGaAs/GaAs quantum dots (QDs) with photonic crystal cavities is demonstrated. Fine adjustment of QD position (within similar to 10nm) and emission energy (few meV) allows construction of coupled QD systems. (C)2008 Optical Society of America

We demonstrate the controllable exciton-cavity mode interaction mediated by pure dephasing in a single site-controlled quantum dot-nanocavity system. With varying detuning, Purcell enhanced dynamics and phonon-assisted cavity feeding sequentially dominate ...

We report on the electric field effects in photoluminescence (PL) and PL excitation (PLE) measurements of reverse-biased GaAs V-groove quantum wires. We observe large redshifts (9 meV at 265 kV/cm) of PL and PLE peaks as well as field dependent intensity and polarization anisotropy variations, which are analyzed by a two-dimensional quantum confined Stark effect model. (C) 1999 American Institute of Physics. [S0003-6951(99)00416-7].

The dynamics of acoustic vibrations in terahertz quantum cascade laser structures (THz-QCLs) is studied by means of femtosecond pump-probe spectroscopy. The phonon modes are characterized by the folding of the acoustic dispersion into an effective reduced ...

The structural and optical properties of controlled-heterostructure-potential, low-dimensional GaAs/AlGaAs nanostructures self-formed during organometallic chemical vapor deposition in tetrahedral pyramids etched in (111) B-GaAs substrates, are investigate ...

Partial suppression of the spectral diffusion of quantum dot (QD) excitons tuned to resonance of a nano-photonic cavity is reported. The suppression is caused by the Purcell enhancement of the QD-exciton recombination rate, which alters the rate of chargin ...

Alok Rudra

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Integration of multiple site-controlled pyramidal quantum dot systems with photonic-crystal membrane cavities

InGaAs/InGaAsP/InP Edge Emitting Laser Diodes on p-GaAs Substrates Obtained by Localised Wafer Fusion

Symmetries and the Polarized Optical Spectra of Exciton Complexes in Quantum Dots

Effect of growth interruptions on ultra thin InAs/InP quantum grown by chemical beam epitaxy

Integrated Quantum Photonics using Site-Controlled Quantum Dots and Tailored-Potential Photonic Crystals

From Layer-by-Layer Growth to Nanoridge Formation: Selective Area Epitaxy of GaAs by MOVPE

Island formation in ultra-thin InAs/InP quantum wells grown by chemical beam epitaxy

Parabolic tailored-potential quantum-wires grown in inverted pyramids

Temperature Dependence of the Coupling between n-type d-Doping Region and Quantum Dot Assemblies

Valence Band Engineering and Polarization Switching in Quantum Dots grown in Inverted Pyramids

Integration of Site-Controlled Pyramidal Quantum Dots and Photonic Crystal Membrane Cavities

Controllable Pure Dephasing Pathways in Single SiteControlled Pyramidal Quantum Dot - Nanocavity System

Two-dimensional quantum-confined Stark effect in V-groove quantum wires: Excited state spectroscopy and theory

Investigation of coherent acoustic phonons in terahertz quantum cascade laser structures using femtosecond pump-probe spectroscopy

Sub-meV Photoluminescence Linewidth and >106 cm2/Vs Electron Mobility in AlGaAs/GaAs Quantum Wells Grown by Metallorganic Vapor Phase Epitaxy on Slightly Misoriented Substrates

Pyramidal GaAs/AlzGa1-zAs quantum wire/dot systems with controlled heterostructure potential

Very low transperancy currents in double quantum well InGaAs semiconductor lasers with δ doped resonant tunneling

1D photonic band formation and photon localization in finite-size photonic-crystal waveguides

A terahertz quantum cascade. laser grown by low-pressure metalorganic vapor phase epitaxy

Limiting the Spectral Diffusion of Nano-Scale Light Emitters using the Purcell effect in a Photonic-Confined Environment