S shape in polar GaInN/GaN quantum wells: Piezoelectric-field-induced blue shift driven by onset of nonradiative recombination

Langer, Torsten; Pietscher, Hans-Georg; Ketzer, Fedor Alexej; Jönen, H.; Bremers, Heiko; Rossów, U.; Menzel, D.; Hangleiter, A.

doi:10.1103/physrevb.90.205302

Cited by 36 publications

(38 citation statements)

References 51 publications

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“…2 Experimental studies reveal clear fingerprints of these carrier localization effects. [2][3][4][5][6] However, even though highlighted by experimental studies, these effects are still widely ignored in the theoretical modeling of In x Ga 1−x N-based structures. In the present atomistic study we investigate directly the effects of deviations from an ideal structure, taking both random alloy and well-width fluctuations explicitly into account.…”

Section: Introductionmentioning

confidence: 99%

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

Schulz¹,

Marquardt

Coughlan

et al. 2015

SPIE Proceedings

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We present a detailed analysis of wave function localization effects in In x Ga 1−x N alloys and quantum wells. Our work is based on density functional theory to analyze the impact of isolated and clustered In atoms on the wave function localization characteristics in In x Ga 1−x N alloys. We address the electronic structure of In 0.25 Ga 0.25 N/GaN quantum wells by means of an atomistic tight-binding model. Random alloy fluctuations in the quantum well region and well-width fluctuations are explicitly taken into account. The tight-binding model includes strain and built-in field fluctuations arising from the random In distribution. Our density functional theory study reveals increasing hole wave function localization effects when an increasing number of In atoms share the same N atom. We find that these effects are less pronounced for the electrons. Our tight-binding analysis of In 0.25 Ga 0.75 N/GaN quantum wells also reflects this behavior, revealing strong hole localization effects arising from the random In atom distribution. We also show that the excited hole states are strongly localized over an energy range of approximately 50 meV from the top of the valence band. For the quantum wells considered here we observe that well-width fluctuations lead to electron wave function localization effects.

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Section: Introductionmentioning

confidence: 99%

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

Schulz¹,

Marquardt

Coughlan

et al. 2015

SPIE Proceedings

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“…This technique ensured that the resulting transient represented a spectral average of the QW emission, since it is well known that the recombination time in polar InGaN QWs varies across the luminescence linewidth [10][11][12] . The LED devices were probed on-chip and the electroluminescence (EL) emission was collected through the backside of the wafer into an integrating sphere equipped with a wavelength calibrated Si-photodiode.…”

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confidence: 99%

Radiative recombination mechanisms in polar and non-polar InGaN/GaN quantum well LED structures

Badcock

Ali

Zhu

et al. 2016

Applied Physics Letters

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We study the photoluminescence internal quantum efficiency (IQE) and recombination dynamics in a pair of polar and nonpolar InGaN/GaN quantum well (QW) light-emitting diode (LED) structures as a function of excess carrier density and temperature. In the polar LED at 293K, the variation of radiative and non-radiative lifetimes is well described by a modified ABC type model which accounts for the background carrier concentration in the QWs due to unintentional doping. As the temperature is reduced, the sensitivity of the radiative lifetime to excess carrier density becomes progressively weaker. We attribute this behaviour to the reduced mobility of the localised electrons and holes at low temperatures, resulting in a more monomolecular like radiative process. Thus we propose that in polar QWs, the degree of carrier localisation determines the sensitivity of the radiative lifetime to the excess carrier density. In the non-polar LED, the radiative lifetime is independent of excitation density at room temperature, consistent with a wholly excitonic recombination mechanism. These findings have significance for the interpretation of LED efficiency data within the context of the ABC recombination model. *

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“…An alternative explanation for the simultaneous blueshift of the emission band and a quenching of its intensity as observed for (In,Ga)N/GaN(0001) quantum wells (QWs) has been recently proposed by Langer et al 25 Their model relies on the exponential variation of the radiative lifetime with transition energy due to the strong piezoelectric fields within the QWs. An activated nonradiative recombination preferentially quenches the longer living transitions, resulting in an effective blueshift of the emission band.…”

mentioning

confidence: 99%

Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

Feix

Flissikowski

Chèze

et al. 2016

Applied Physics Letters

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We investigate sub-monolayer InN quantum sheets embedded in GaN(0001) by temperature-dependent photoluminescence spectroscopy under both continuous-wave and pulsed excitation. Both the peak energy and the linewidth of the emission band associated with the quantum sheets exhibit an anomalous dependence on temperature indicative of carrier localization. Photoluminescence transients reveal a power law decay at low temperatures reflecting that the recombining electrons and holes occupy spatially separate, individual potential minima reminiscent of conventional (In,Ga)N(0001) quantum wells exhibiting the characteristic disorder of a random alloy. At elevated temperatures, carrier delocalization sets in and is accompanied by a thermally activated quenching of the emission. We ascribe the strong nonradiative recombination to extended states in the GaN barriers and confirm our assumption by a simple rate-equation model.

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S shape in polar GaInN/GaN quantum wells: Piezoelectric-field-induced blue shift driven by onset of nonradiative recombination

Cited by 36 publications

References 51 publications

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

Radiative recombination mechanisms in polar and non-polar InGaN/GaN quantum well LED structures

Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

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S shape in polar GaInN/GaN quantum wells: Piezoelectric-field-induced blue shift driven by onset of nonradiative recombination

Cited by 36 publications

References 51 publications

Atomistic description of wave function localization effects in InxGa1-xN alloys and quantum wells

Atomistic description of wave function localization effects in InxGa1-xN alloys and quantum wells

Radiative recombination mechanisms in polar and non-polar InGaN/GaN quantum well LED structures

Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

Contact Info

Product

Resources

About

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells