Scaling quantum-dot light-emitting diodes to submicrometer sizes

Fiore, Andrea; Chen, Jx X.; Ilegems, M.

doi:10.1063/1.1504880

Cited by 45 publications

(44 citation statements)

References 16 publications

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“…First, two emission lines dominate the spectrum: the exciton (X) and biexciton (BX). As previously demonstrated [4][5][6][7][8][9], the identification follows from the power dependence of the integrated PL intensity. On average the exciton intensity is proportional to P 0.7±0.1 and the BX to P…”

Section: Resultsmentioning

confidence: 95%

Time resolved measurements on low‐density single quantum dots at 1300 nm

Zinoni¹,

Alloing

Monat

et al. 2006

Phys. Status Solidi (c)

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Published online zzz PACS 78.67. Hc, 78.66.Fd, 78.47.+p We present time integrated and time resolved measurements on single In/As quantum dots (QD) emitting at 1300nm, at 10K, embedded in a planar microcavity. We clearly identify a standard spectroscopic signature from single QDs and compare the exciton line width and biexciton (BX) binding energy for several QDs. We present this data for QDs spatially selected by etched mesas and metallic apertures. Time resolved photoluminescence (PL) from single electron-hole recombination in the ground state of the QD is investigated as a function of excitation power and temperature. The measurements reveal the presence of a background emission that delays the PL of excitons in the ground state.1 Introduction Efficient generation of single photons on demand at telecom wavelength (1310nm and 1550nm) is crucial for quantum key distribution (QKD). The optical properties of single quantum dots (QDs) have the potential for satisfying the requirements of a convenient single photon source: QDs can be grown in conventional semiconductor epitaxial systems and the nature of the 3D confinement of the wavefunction generates atomic-like spectral features. A single QD can be populated by several electron-hole pairs (excitons), each recombining to emit a photon. Due to Coulomb interactions originating from the strong charge confinement, the energy levels are shifted and each transition can be spectrally isolated to produce a single photon source. QDs that emit in the spectral range where silicon technology is used have been extensively studied [1][2][3]. However, the attenuation in optical fibers below 1270nm restricts the potential use of these QDs in QKD applications. Working with QDs emitting in the telecom window presents several challenges: first the QD emission has to be red shifted while maintaining a low spatial density-a difficult combination of requirements for conventional epitaxial growth methods. Second, the single photon detection technology for the near infrared is still in its infancy: noise levels, quantum efficiency, and temporal response are considerably poorer when compared to the single photon detection modules operating below 1000nm. Recently we have demonstrated [4] a technique for achieving ultra low areal densities (1-2 dots/µm2) and large dot sizes for emission in the 1300nm band. In combination with ultra small light-emitting diode structures [5][6], they could lead to electrically pumped single photon sources. These QDs present several distinct features, as compared to widely studied short-wavelength QDs, such as larger confinement energy, higher strain fields, and consequently different electron-hole wave functions. Time-resolved studies on single exciton transitions provide important information on the dynamics of the electron-hole relaxation into these new QDs and may change the way in which QD based single photon devices are operated. In this work we compare the photoluminescence from the ground state of the QDs spatially isolated by two different methods...

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Section: Resultsmentioning

confidence: 95%

Time resolved measurements on low‐density single quantum dots at 1300 nm

Zinoni¹,

Alloing

Monat

et al. 2006

Phys. Status Solidi (c)

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“…As shown in Ref. 12, we expect current spreading and carrier diffusion to be negligible in this structure. Despite a high turn-on voltage (due to unoptimized p-doping in the top mirror), all curves can be fitted with a single oxidized length parameter that is also consistent with the SEM estimate.…”

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confidence: 95%

“…The QD LEDs are designed to be efficient devices only for the one or few QDs that are resonant with the cavity mode: the ultimate goal is to demonstrate enhancement of spontaneous emission from a single emitter which requires high quality factors and small mode volumes. Optimization of these parameters compromises the efficiency 12 for the QD ensemble. The cw electroluminescence spectra at 293 K are presented in logarithmic scale in Fig.…”

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confidence: 99%

Three-dimensional wavelength-scale confinement in quantum dot microcavity light-emitting diodes

Zinoni

Alloing

Paranthoën

et al. 2004

Applied Physics Letters

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We introduce a microcavity light-emitting diode (LED) structure that uses submicrometer oxide aperture and a quantum dot active region to achieve strong three-dimensional confinement of both the carrier distribution and the optical field. Light–current curves show optical emission for devices as small as 400nm in diameter. Spectroscopy on electrically pumped LEDs, with apertures ranging from 2.5 down to 0.7μm, show several spectral lines corresponding to cavity modes. A strong blueshift of the resonant modes for smaller apertures demonstrates the role of the oxide aperture in confining laterally the optical wave in a volume comparable to (λ∕n)3. Due to the high quality factors and low mode volumes, the devices could be good candidates for the demonstration of the Purcell effect under electrical pumping.

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“…Selective oxidation of the AlGaAs cladding layers, which has been extensively used in optoelectronic device fabrication, [12][13][14][15][16][17][18] was investigated here as a means to reduce the influence of the surface by reducing carrier diffusion to the etched surfaces. Some of the samples were placed in an oxidation furnace after the etch step to selectively oxidize the Al 0.9 Ga 0.1 As layers.…”

Section: Design and Fabricationmentioning

confidence: 99%

Low effective surface recombination in In(Ga)As/GaAs quantum dot diodes

Tanriseven

Corbett

2011

Journal of Applied Physics

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Size dependent current-voltage measurements were performed on InGaAs quantum dot active region mesa diodes and the surface recombination velocity was extracted from current density versus perimeter/area plots using a diffusion model. An effective surface recombination value of 5.5 x 10(4) cm/s was obtained that can be reduced by more than an order of magnitude by selective oxidation of Al(0.9)Ga(0.1)As cladding layers. The values are three times smaller than those obtained for a single quantum well. The effect of p-type doping in the active region was investigated and found to increase the effective surface recombination. (C) 2011 American Institute of Physics. [doi:10.1063/1.3611387

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Scaling quantum-dot light-emitting diodes to submicrometer sizes

Cited by 45 publications

References 16 publications

Time resolved measurements on low‐density single quantum dots at 1300 nm

Time resolved measurements on low‐density single quantum dots at 1300 nm

Three-dimensional wavelength-scale confinement in quantum dot microcavity light-emitting diodes

Low effective surface recombination in In(Ga)As/GaAs quantum dot diodes

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