Donor-acceptor-like behavior of electron-hole pair recombinations in low-dimensional (Ga,In)N/GaN systems

Morel, Aurélien; Lefèbvre, Pierre; Kalliakos, Sokratis; Taliercio, Thierry; Bretagnon, Thierry; Gil, Bernard

doi:10.1103/physrevb.68.045331

Cited by 96 publications

(107 citation statements)

References 34 publications

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“…First, in polar (In,Ga)N QWs the decay occurs over a much longer time scale due to the polarization field perpendicular to the plane of the QWs [45,[47][48][49]. Second, the decay curves are nonexponential due to the variable in-plane separation of the separately localized electrons and holes [46,49]. Single-exponential decays in nonpolar QWs have also been reported by other groups [44,50].…”

Section: B Experimental Results: Optical Characterizationmentioning

confidence: 54%

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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Section: B Experimental Results: Optical Characterizationmentioning

confidence: 54%

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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show abstract

“…This is particularly important in the case of InGaN QWs as the radiative lifetime is not only governed by the electron/hole wavefunction separation perpendicular to the growth plane but also the local microstructure that can influence the in-plane wavefunction overlap. 30 By recording the PL decay transients at 10 K, as shown in Fig. 3, we obtain a measure of the radiative recombination lifetime at the luminescence peak.…”

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confidence: 99%

Effects of quantum well growth temperature on the recombination efficiency of InGaN/GaN multiple quantum wells that emit in the green and blue spectral regions

Hammersley

Kappers

Massabuau

et al. 2015

Applied Physics Letters

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InGaN-based light emitting diodes and multiple quantum wells designed to emit in the green spectral region exhibit, in general, lower internal quantum efficiencies than their blue-emitting counter parts, a phenomenon referred to as the “green gap.” One of the main differences between green-emitting and blue-emitting samples is that the quantum well growth temperature is lower for structures designed to emit at longer wavelengths, in order to reduce the effects of In desorption. In this paper, we report on the impact of the quantum well growth temperature on the optical properties of InGaN/GaN multiple quantum wells designed to emit at 460 nm and 530 nm. It was found that for both sets of samples increasing the temperature at which the InGaN quantum well was grown, while maintaining the same indium composition, led to an increase in the internal quantum efficiency measured at 300 K. These increases in internal quantum efficiency are shown to be due reductions in the non-radiative recombination rate which we attribute to reductions in point defect incorporation.

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“…5. The non-exponential shape of the decay transients, attributed to the variation in the in-plane separation of the independently localised electrons and holes [19], means that they cannot be described using a single decay constant. Instead, we characterise the PL decay time scale by the time required for the PL intensity to fall to 1/e of its maximum value (τ 1/e ).…”

Section: Resultsmentioning

confidence: 99%

Room temperature PL efficiency of InGaN/GaN quantum well structures with prelayers as a function of number of quantum wells

Christian

Hammersley

Davies

et al. 2016

Phys. Status Solidi C

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We report on the effects of varying the number of quantum wells (QWs) in an InGaN/GaN multiple QW (MQW) structure containing a 23 nm thick In0.05Ga0.95N prelayer doped with Si. The calculated conduction and valence bands for the structures show an increasing total electric field across the QWs with increasing number of QWs. This is due to the reduced strength of the surface polarisation field, which opposes the built‐in field across the QWs, as its range is increased over thicker samples. Low temperature photoluminescence (PL) measurements show a red shifted QW emission peak energy, which is attributed to the enhanced quantum confined Stark effect with increasing total field strength across the QWs. Low temperature PL time decay measurements and room temperature internal quantum efficiency (IQE) measurements show decreasing radiative recombination rates and decreasing IQE, respectively, with increasing number of QWs. These are attributed to the increased spatial separation of the electron and hole wavefunctions, consistent with the calculated band profiles. It is also shown that, for samples with fewer QWs, the reduction of the total field across the QWs makes the radiative recombination rate sufficiently fast that it is competitive with the efficiency losses associated with the thermal escape of carriers. (© 2016 The Authors. Phys. Status Solidi C published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Donor-acceptor-like behavior of electron-hole pair recombinations in low-dimensional (Ga,In)N/GaN systems

Cited by 96 publications

References 34 publications

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

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

Effects of quantum well growth temperature on the recombination efficiency of InGaN/GaN multiple quantum wells that emit in the green and blue spectral regions

Room temperature PL efficiency of InGaN/GaN quantum well structures with prelayers as a function of number of quantum wells

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