Single dot photoluminescence excitation spectroscopy in the telecommunication spectral range

Podemski, P.; Maryński, A.; Wyborski, Paweł; Bercha, Artem; Trzeciakowski, Witold; Sęk, G.

doi:10.1016/j.jlumin.2019.04.058

Cited by 13 publications

(4 citation statements)

References 31 publications

(52 reference statements)

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“…Both these values correspond well with the energy difference between the excited and ground quantum dot states expected from the measurements on an ensemble of similar QDs. 19) The linewidths of the PLE maxima are relatively broad (~2 meV), which may be related to the relatively large excitation laser linewidth (~0.7 meV) 18) or can result from a complex energy structure (i.e. dense ladder of states) of the QD excited states.…”

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confidence: 99%

“…For the identification of excited state in these quantum dots there was used single-dot photoluminescence excitation (PLE) spectroscopy adapted to the spectral range above 1 µm. 18) QDs were excited by a self-made continuous wave external-cavity tunable laser followed by a short-focallength monochromator and shortpass filters to provide a clean excitation laser line. For the nonresonant excitation a 639 nm semiconductor laser was used.…”

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confidence: 99%

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Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μ m

Podemski

Musiał

Gawarecki

et al. 2020

Applied Physics Letters

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The electronic structure of strain-engineered In0.75Ga0.25As/GaAs quantum dots emitting in the telecommunication O band is probed experimentally by photoluminescence excitation spectroscopy on the single-dot level. The observed resonances are attributed to p-shell states of individual quantum dots. The determined energy difference between s-and p-shells shows an inverse dependence on the emission energy. This observation is attributed to the varying indium content within individual quantum dots, indicating a way to control the quantum dot electronic structure. The impact of the size and indium content in the investigated quantum dots is simulated with an 8-band k·p model supporting the interpretation of the experimental data. † Present address:

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confidence: 99%

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confidence: 99%

Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μ m

Podemski

Musiał

Gawarecki

et al. 2020

Applied Physics Letters

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“…During this, the material, mainly from their tops, becomes mixed into the top barrier material layer. Very recently, microphotoluminescence excitation 25 studies of such InAs/InP QDs showed that they possibly have a peculiar feature, namely, that the s – p -shell splitting for excitons in such systems may follow dependence on emission energy, which is opposite to the standard increasing one 26 . There was a single report on similar behavior of InAs/GaAs QDs with a strain-reducing layer, which was attributed to a strong variation of average In content within QD ensemble with a specific form of composition gradient within a QD 27 .…”

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confidence: 99%

Atypical dependence of excited exciton energy levels and electron-hole correlation on emission energy in pyramidal InP-based quantum dots

Gawełczyk

2022

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We calculate the spectrum of excited exciton states in application-relevant self-assembled pyramidal quantum dots grown in InAs/InP and InAs/AlGaInAs material systems. These types of dots have been recently shown to combine the emission in the third optical fiber window with low surface density and a reasonable level of in-plane symmetry of emitters, which predestines them for studies on single- and entangled-photon emission and for corresponding applications. The spectrum of optically active excited states is crucial for successful resonant and quasi-resonant excitation of emitters, allowing for conservation of angular momentum and addressing individual selected quantum states. Here, we show that in both types of studied dots, due to their specific morphology of truncated pyramid, the density of excited-state ladder, especially the s–p shell splitting may follow an unconventional dependence on emission energy, opposite to the one typically met in regular quantum dots. We obtain this result via modeling based on available morphological data and calculation within the multi-band $${{\varvec{k}} {\cdot } {\varvec{p}}}$$ k · p envelope-function theory combined with the configuration-interaction method used to calculate exciton states. Then, we explain this observation in purely geometric terms, as a result of an increasing effective quantum confinement width in a pyramid that is progressively cut from the top. Additionally, we show that the inverted trend is also manifested in the amount of electron-hole correlation in the exciton ground state, which also shows an anomalous dependence on emission energy and quantum dot volume.

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“…Here, we use an experimental setup built for PLE studies of single nanostructures (µPLE) emitting in the infrared [31], especially in the third telecom window. We successfully probe the spectrum of optically active excited states of C-band-emitting QDs elongated above 100 nm, including individual bright states forming the exciton fine structure, and the negatively charged exciton (X − ).…”

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Excited states of neutral and charged excitons in single strongly asymmetric InP-based nanostructures emitting in the telecom C band

et al. 2019

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We investigate strongly asymmetric self-assembled nanostructures with one of dimensions reaching hundreds of nanometers. Close to the nanowire-like type of confinement, such objects are sometimes assigned as one-dimensional in nature. Here, we directly observe the spectrum of exciton excited states corresponding to longitudinal quantization. This is based on probing the optical transitions via polarization-resolved microphotoluminescence excitation (µPLE) measurement performed on single nanostructures combined with theoretical calculation of neutral and charged exciton optical properties. We successfully probe absorption-like spectra for individual bright states forming the exciton ground-state fine structure, as well as for the negatively charged exciton. Confronting the calculated spectrum of excitonic absorption with µPLE traces, we identify optical transitions involving states that contain carriers at various excited levels related to the longest dimension. Based on cross-polarized excitation-detection scheme, we show very well conserved spin configuration during orbital relaxation of the exciton from a number of excited states comparable to the quasi-resonant pumping via the optical phonon, and no polarization memory for the trion, as theoretically expected.

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Single dot photoluminescence excitation spectroscopy in the telecommunication spectral range

Cited by 13 publications

References 31 publications

Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μ m

Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μ m

Atypical dependence of excited exciton energy levels and electron-hole correlation on emission energy in pyramidal InP-based quantum dots

Excited states of neutral and charged excitons in single strongly asymmetric InP-based nanostructures emitting in the telecom C band

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