Polarization dependence of electroluminescence from closely-stacked and columnar quantum dots

Ridha, Philipp; Li, Lianhe; Rossetti, M.; Patriarche, G.; Fiore, Andrea

doi:10.1007/s11082-007-9173-6

Cited by 28 publications

(24 citation statements)

References 13 publications

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“…Self assembled QDs have low aspect ratios (typically 0.1 to 0.3) and strong carrier confinement along [001], resulting in very anisotropic optical properties, whereby the TE optical mode is dominant and the TM optical mode can be very weak. Large aspect ratio (> 0.6) columnar QDs 9,10 have been designed in order to achieve isotropic in-plane polarization. Here we calculate the polarization dependent optical transitions for our SQD sample and compare it to the response of our GaAs capped and InGaAs SRCL capped bilayers, shown in Figs.…”

Section: F Te/tm Ratio Analysismentioning

confidence: 99%

Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)

Usman

Heck

Clarke

et al. 2011

Journal of Applied Physics

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The design of some optical devices such as semiconductor optical amplifiers for telecommunication applications requires polarization-insensitive optical emission at the long wavelengths (1300-1550 nm). Self-assembled InAs/GaAs quantum dots (QDs) typically exhibit ground state optical emission at wavelengths shorter than 1300 nm with highly polarization-sensitive characteristics, although this can be modified by using low growth rates, the incorporation of strainreducing capping layers or growth of closely-stacked QD layers. Exploiting the strain interactions between closely stacked QD layers also allows greater freedom in the choice of growth conditions for the upper layers, so that both a significant extension in their emission wavelength and an improved polarization response can be achieved due to modification of the QD size, strain and composition. In this paper we investigate the polarization behavior of single and stacked QD layers using room temperature sub-lasing-threshold electroluminescence and photovoltage measurements as well as atomistic modeling with the NEMO 3-D simulator. A reduction is observed in the ratio of the transverse electric (TE) to transverse magnetic (TM) optical mode response for a GaAs-capped QD stack compared to a single QD layer, but when the second layer of the two-layer stack is InGaAs-capped an increase in the TE/TM ratio is observed, in contrast to recent reports for single QD layers.

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Section: F Te/tm Ratio Analysismentioning

confidence: 99%

Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)

Usman

Heck

Clarke

et al. 2011

Journal of Applied Physics

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“…The active layer of the device consists of alternately stacked InAs island layers and GaAs intermediate layers. This configuration can significantly increase areal dot density and the modal gain of the SOA [18] and the gain is nearly polarization independent [23]. The density of state of the InAs/InGaAsP/InP QD-SOA [24] is shown in Figure 1 (a).…”

Section: Qd-soa Structure and Rate Equationsmentioning

confidence: 99%

High Speed All-Optical Logic Gate Using QD-SOA and its Application

Zhao¹,

Hu²

2017

Preprint

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Abstract:The scheme to realize high speed (~250Gb/s) all-optical Boolean logic gates using semiconductor optica amplifiers with quantum-dot (QD-SOA) is introduced and analyzed in this review. Numerical simulation method was presented by solving the rate equation and taking into account nonlinear dynamics including carrier heating and spectral hole-burning. Binary phase shift keyed (BPSK) signal and on-off keyed signal are used to generate high speed all-optical logic gates. The applications based on all-optical logic gates such as, all-optical latches, pseudo random bit sequence (PRBS) generation and all-optical encryption, are also discussed in this review. Results show that the scheme based on QD-SOA is a promising method for the realization of high speed all-optical communication system in the future.

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“…The shape anisotropy has been engineered either embedding a single layer of QDs into InGaAs strain reducing layers [16,17], or by closely stacked QDs (CSQDs) [15] and columnar QDs (CQDs) [10] formed by several repetitions of ML-thin InAs/GaAs layers. In particular, the last two QD geometries have shown a significant enhancement of TM-mode photoluminescence [3,5,8,19] due to a reduction of the biaxial strain in the centre of the CQDs and CSQDs.…”

Section: Introductionmentioning

confidence: 99%

Tuning of polarization sensitivity in closely stacked trilayer InAs/GaAs quantum dots induced by overgrowth dynamics

Tasco

Usman²,

Giorgi

et al. 2014

Nanotechnology

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Abstract:Tailoring electronic and optical properties of self-assembled InAs quantum dots (QDs) is a critical limit for the design of several QD-based optoelectronic devices operating in the telecom frequency range. We describe how a fine control of the strain-induced surface kinetics during the growth of vertically-stacked multiple layers of QDs allow to engineer their self organization process. Most noticeably, the present study shows that the underlying strain field induced along a QD stack can be modulated and controlled by time-dependent intermixing and segregation effects occurring after capping with GaAs spacer. This leads to a drastic increase of TM/TE polarization ratio of emitted light, not accessible from the conventional growth parameters. Our detailed experimental measurements supported by comprehensive multi-million atom simulations of strain, electronic, and optical properties, provide in-depth analysis of the grown QD samples leading us to depict a clear picture on atomic scale phenomena affecting the proposed growth dynamics and consequent QD polarization response.

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Polarization dependence of electroluminescence from closely-stacked and columnar quantum dots

Cited by 28 publications

References 13 publications

Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)

Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)

High Speed All-Optical Logic Gate Using QD-SOA and its Application

Tuning of polarization sensitivity in closely stacked trilayer InAs/GaAs quantum dots induced by overgrowth dynamics

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