J. Y. Marzin

Structural and optical properties of high quality InAs/GaAs short-period superlattices grown by migration-enhanced epitaxy

InAs/GaAs highly strained short‐period superlattices have been grown by migration‐enhanced epitaxy on InP(001) substrates. Such samples exhibit clearly improved structural and optical properties. X‐ray diffraction, scanning transmission electron microscopy, photoluminescence, and Raman scattering experiments have been performed to characterize an (InAs)4(GaAs)3 layer.

Giant Rabi splitting in a microcavity containing distributed quantum wells

We present a microcavity design where the overlap between quantum well excitons and the electromagnetic field is much larger than in previously reported structures: quantum wells are located not only in the central cavity layer but also in the Bragg mirrors. We obtain a Rabi splitting of 19 meV. Since the Rabi splitting is larger than the exciton binding energy, exciton excited states have to be taken into account in the reflectivity calculation to describe the spectral shape of the two polariton lines.

Nano-fabrication with focused ion beams

Controlled and reproducible fabrication of nano-structured materials will constitute one of the main industrial challenges for the next 10 years. To overcome the severe limitations of existing nano-fabrication techniques, we have developed and improved the ultimate usable resolution of an innovative focused ion beam instrument (FIB). In this work we demonstrate that FIB techniques allow quite simple, direct, clean and reproducible material nano-structuring close to or below the 10 nm level.

Time-resolved characterization of InAsP∕InP quantum dots emitting in the C-band telecommunication window

The dynamic response of InAsP quantum dots grown on InP(001) substrates by low-pressure Metalorganic Vapor Phase Epitaxy emitting around 1.55

Strong and weak coupling regime in pillar semiconductor microcavities

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Evidence of depth and lateral diffusion of defects during focused ion beam implantation

m, is investigated by means of time-resolved microphotoluminescence as a function of temperature. Exciton lifetime steadily increases from 1 ns at low temperature to reach 4 ns at 300K while the integrated photoluminescence intensity decreases only by a factor of 2/3. These characteristics give evidence that such InAsP/InP quantum dots provide a strong carrier confinement even at room temperature and that their dynamic response is not affected by thermally activated non-radiative recombination up to room temperature.

GAAS/ALGAAS QUANTUM WIRES FABRICATED BY SIO2 CAPPING-INDUCED INTERMIXING

Abstract We present photoluminescence measurements in pillar microcavities containing GaAs quantum wells. The strong coupling regime between excitons and zero-dimensional photon modes is evidenced by a characteristic anticrossing behavior, with a constant Rabi splitting down to 1xa0μm radius. Moreover, since semiconductor Bragg mirrors have a finite angular acceptance, a large fraction of the radiant excitons are weakly coupled to the leaky modes. We show that this emission is confined in the pillar and diffracted through the top surface. Its relative intensity increases when reducing the pillar radius. We also report the largest Rabi splitting ever obtained in III–V compounds using a microcavity filled-up with quantum wells.

InAs quantum boxes in GaAs/AlAs pillar microcavities: from spectroscopic investigations to spontaneous emission control

We have investigated the evolution of the photoluminescence intensity of different GaAs/GaAlAs quantum wells to probe the defect penetration during focused ion beam implantation at various sample temperatures. By implanting homogeneous areas, it was possible to evaluate the depth extension of the ion-induced damage, while by localizing the implantation at a submicrometric length scale, it was also possible to quantify the lateral damage extension. Both the depth and lateral damage extensions are found to be reduced when the sample temperature is changed from 300 to 80 K. This result is used to demonstrate that a fast diffusion of nonequilibrium defects is taking place in the irradiated sample. It is found that this diffusion is highly anisotropic with a lateral diffusion length ten times higher than the depth one, suggesting that the defects easily diffuse in the GaAlAs barrier layers. The results are interpreted as a manifestation of a radiation enhanced diffusion mechanism. The advantage of using low temperature irradiations to better localize the injected defects by focused ion beam is highlighted, specially for quantum nanostructure fabrication.We have investigated the evolution of the photoluminescence intensity of different GaAs/GaAlAs quantum wells to probe the defect penetration during focused ion beam implantation at various sample temperatures. By implanting homogeneous areas, it was possible to evaluate the depth extension of the ion-induced damage, while by localizing the implantation at a submicrometric length scale, it was also possible to quantify the lateral damage extension. Both the depth and lateral damage extensions are found to be reduced when the sample temperature is changed from 300 to 80 K. This result is used to demonstrate that a fast diffusion of nonequilibrium defects is taking place in the irradiated sample. It is found that this diffusion is highly anisotropic with a lateral diffusion length ten times higher than the depth one, suggesting that the defects easily diffuse in the GaAlAs barrier layers. The results are interpreted as a manifestation of a radiation enhanced diffusion mechanism. The advantage of using low te...

Interdiffusion of GaAs/GaAlAs quantum wells enhanced by low energy gallium focused ion beam implantation

We demonstrate that selective intermixing of GaAs/AlGaAs quantum well heterostructures induced by SiO2 capping and subsequent annealing can be spatially localized on a length scale compatible with the lateral confinement of carriers into quantum wires. Low temperature optical spectroscopy measurements including linear polarization anisotropy analysis show evidence of the formation of one‐dimensional subbands. A mechanism involving the ability of the thermal stress field generated in the heterostructure by the patterned SiO2 film to pilot the diffusion of the excess Ga vacancies, which are responsible for the enhanced interdiffusion under SiO2 is suggested to account for the high lateral selectivity achievable with this novel process.

Focused ion beam patterning of III–V crystals at low temperature: A method for improving the ion-induced defect localization

Abstract GaAs/AlAs pillar microcavities containing an array of InAs quantum boxes in their core region have been fabricated by molecular beam epitaxy, electron-beam lithography and reactive ion etching. By placing this broadband light emitter in the cavity, we can probe precisely by photoluminescence the modal structure of the micropillars. After having validated this approach through the study of circular pillars, we address two important issues in context of spontaneous emission control. We show first that it is possible, by choosing an elliptical cross-section, to lift the polarization degeneracy of the fundamental mode of circular micropillars. By measuring Purcell’s factor for small pillars containing quantum boxes, we then highlight their potential for observing large cavity quantum electrodynamic effects in the weak coupling regime, which is confirmed by recent preliminary time-resolved experiments.