Quantum confined Stark effect due to built-in internal polarization fields in (Al,Ga)N/GaN quantum wells

Leroux, M.; Grandjean, N.; Laügt, M.; Massies, J.; Gil, Bernard; Lefèbvre, Pierre; Bigenwald, Pierre

doi:10.1103/physrevb.58.r13371

Cited by 428 publications

(256 citation statements)

References 19 publications

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“…This is a consequence of a quantum confined Stark effect due to a strong internal electric field in the quantum structure. This effect is reinforced in [7]. They are plotted in Fig.…”

Section: Resultsmentioning

confidence: 87%

“…However, there is still only a few reports on the physical properties of nitride QWs compared to what is known about the prototypical system AlGaAs/GaAs. This is especially the case when considering the AlGaN/GaN QWs [2][3][4][5][6][7][8] though they appear very promising for extending the applications of nitrides to the far UV spectral region owing to the large direct band gap of AlN (6.2 eV/200 nm). It has been already shown that a large internal electric field of several hundred kV/cm takes place in the wurtzite AlGaN/GaN QWs [2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Optical and Structural Properties of AlGaN/GaN Quantum Wells Grown by Molecular Beam Epitaxy

Grandjean

Massies

Leroux

et al. 1999

MRS Internet j. nitride semicond. res.

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AlGaN/GaN quantum well (QWs) were grown on (0001) sapphire substrates by molecular beam epitaxy (MBE) using ammonia as nitrogen precursor. The Al composition in the barriers was varied between 8 and 27 % and the well thickness from 4 to 17 monolayers (MLs, 1ML = 2.59Å). X-ray diffraction (XRD) experiments are used to investigate the strain state of both the well and the barriers. The QW transition energy are measured by low temperature photoluminescence (PL). A large quantum confined Stark effect is observed leading to QW luminescence much lower than the emission line of the GaN buffer layer for well width above a certain critical thickness. The built-in electric field responsible for such a phenomenon is deduced from fit of the PL data. Its magnitude is of several hundred kV/cm and increases linearly with the Al composition.

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“…This is a consequence of a quantum confined Stark effect due to a strong internal electric field in the quantum structure. This effect is reinforced in [7]. They are plotted in Fig.…”

Section: Resultsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Optical and Structural Properties of AlGaN/GaN Quantum Wells Grown by Molecular Beam Epitaxy

Grandjean

Massies

Leroux

et al. 1999

MRS Internet j. nitride semicond. res.

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“…The consequences of this electric field on the emission properties are detrimental as it decreases the overlap between the electron and hole wave functions. 2 This so-called quantum confined Stark effect ͑QCSE͒ leads to a spectral redshift and to a dramatic increase in the radiative lifetime, worsening the influence of fast nonradiative processes. The growth of nitride heterostructures along a nonpolar direction ͑i.e., perpendicular to the c-axis͒ is consequently a way to overcome the QCSE ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Exciton localization on basal stacking faults in a-plane epitaxial lateral overgrown GaN grown by hydride vapor phase epitaxy

Corfdir

Lefèbvre

Levrat

et al. 2009

Journal of Applied Physics

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104

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We present a detailed study of the luminescence at 3.42 eV usually observed in a-plane epitaxial lateral overgrowth ͑ELO͒ GaN grown by hydride vapor phase epitaxy on r-plane sapphire. This band is related to radiative recombination of excitons in a commonly encountered extended defect of a-plane GaN: I 1 basal stacking fault. Cathodoluminescence measurements show that these stacking faults are essentially located in the windows and the N-face wings of the ELO-GaN and that they can appear isolated as well as organized into bundles. Time-integrated and time-resolved photoluminescence, supported by a qualitative model, evidence not only the efficient trapping of free excitons ͑FXs͒ by basal plane stacking faults but also some localization inside I 1 stacking faults themselves. Measurements at room temperature show that FXs recombine efficiently with rather long luminescence decay times ͑360 ps͒, comparable to those encountered in high-quality GaN epilayers. We discuss the possible role of I 1 stacking faults in the overall recombination mechanism of excitons.

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“…However, when trying to push the emission wavelength into the green to yellow spectral region the device performance is hampered, among other factors, by the presence of strong electrostatic built-in fields, arising in part from the strain-dependent piezoelectric polarization and in part from the strain-independent spontaneous polarization [3]. One consequence of the built-in field is the so-called quantum confined Stark effect (QCSE) which results in a shift of the emission to longer wavelength [4,5]. Also the intrinsic field leads to a spatial separation of electron and hole wave functions, causing a reduced radiative recombination rate [4,6], an effect that can be particularly undesirable for high-efficiency optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Structural, electronic, and optical properties ofm-plane InGaN/GaN quantum wells: Insights from experiment and atomistic theory

Schulz¹,

Tanner

O’Reilly

et al. 2015

Phys. Rev. B

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In this paper we present a detailed analysis of the structural, electronic, and optical properties of an m-plane (In,Ga)N/GaN quantum well structure grown by metal organic vapor phase epitaxy. The sample has been structurally characterized by x-ray diffraction, scanning transmission electron microscopy, and 3D atom probe tomography. The optical properties of the sample have been studied by photoluminescence (PL), time-resolved PL spectroscopy, and polarized PL excitation spectroscopy. The PL spectrum consisted of a very broad PL line with a high degree of optical linear polarization. To understand the optical properties we have performed atomistic tight-binding calculations, and based on our initial atom probe tomography data, the model includes the effects of strain and built-in field variations arising from random alloy fluctuations. Furthermore, we included Coulomb effects in the calculations. Our microscopic theoretical description reveals strong hole wave function localization effects due to random alloy fluctuations, resulting in strong variations in ground state energies and consequently the corresponding transition energies. This is consistent with the experimentally observed broad PL peak. Furthermore, when including Coulomb contributions in the calculations we find strong exciton localization effects which explain the form of the PL decay transients. Additionally, the theoretical results confirm the experimentally observed high degree of optical linear polarization. Overall, the theoretical data are in very good agreement with the experimental findings, highlighting the strong impact of the microscopic alloy structure on the optoelectronic properties of these systems.

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Quantum confined Stark effect due to built-in internal polarization fields in (Al,Ga)N/GaN quantum wells

Cited by 428 publications

References 19 publications

Optical and Structural Properties of AlGaN/GaN Quantum Wells Grown by Molecular Beam Epitaxy

Optical and Structural Properties of AlGaN/GaN Quantum Wells Grown by Molecular Beam Epitaxy

Exciton localization on basal stacking faults in a-plane epitaxial lateral overgrown GaN grown by hydride vapor phase epitaxy

Structural, electronic, and optical properties ofm-plane InGaN/GaN quantum wells: Insights from experiment and atomistic theory

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