Electron leakage effects on GaN-based light-emitting diodes

Piprek, Joachim; Li, Simon

doi:10.1007/s11082-011-9437-z

Cited by 103 publications

(57 citation statements)

References 20 publications

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“…10 shows that, with the selected values of material parameters, numerical simulations predict essentially no electron leakage from the active region into the p-cap at a current I = 100 mA where droop is already significant in low-TDD structures, over the entire temperature range 15-120 • C. (As discussed in Ref. 45, electron leakage may become less relevant for increasing temperature.) From the same figure, the importance of current crowding may be appreciated by comparing the J n, y (y) profiles at different lateral coordinates.…”

Section: A Realistic Spatial Distribution Of Carriers In the Active mentioning

confidence: 90%

“…uncertainties in the valence band offset at the barrier/EBL interface. 45 Some effects of model and structural parameter variability will be addressed in Section V.…”

Section: D Simulation Studymentioning

confidence: 99%

“…it would be compatible with Auger processes in InGaN/GaN QWs rather than with density-activated defect recombination or leakage from the active region, both decreasing with increasing temperature. 26,29,45 However, in our opinion, an accurate determination of the actual Auger rates remains elusive to a combined experimental and simulation analysis based on state-of-the-art DD-based optoelectronic CAD tools, not only because the applicability of the ABC model to QWs is somehow questionable, also strongly affected by the microscopic details of the MQW heterostructures. If the relationship between recombination coefficients in bulk and in QWs is not better explored, beyond the attempt presented in Ref.…”

Section: Auger Recombination and Auger-related Processesmentioning

confidence: 99%

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Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

et al. 2014

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Electroluminescence (EL) characterization of InGaN/GaN light-emitting diodes (LEDs), coupled with numerical device models of different sophistication, is routinely adopted not only to establish correlations between device efficiency and structural features, but also to make inferences about the loss mechanisms responsible for LED efficiency droop at high driving currents. The limits of this investigative approach are discussed here in a case study based on a comprehensive set of currentand temperature-dependent EL data from blue LEDs with low and high densities of threading dislocations (TDs). First, the effects limiting the applicability of simpler (closed-form and/or one-dimensional) classes of models are addressed, like lateral current crowding, vertical carrier distribution nonuniformity, and interband transition broadening. Then, the major sources of uncertainty affecting state-of-the-art numerical device simulation are reviewed and discussed, including (i) the approximations in the transport description through the multi-quantum-well active region, (ii) the alternative valence band parametrizations proposed to calculate the spontaneous emission rate, (iii) the difficulties in defining the Auger coefficients due to inadequacies in the microscopic quantum well description and the possible presence of extra, non-Auger high-current-density recombination mechanisms and/or Auger-induced leakage. In the case of the present LED structures, the application of three-dimensional numerical-simulation-based analysis to the EL data leads to an explanation of efficiency droop in terms of TD-related and Auger-like nonradiative losses, with a C coefficient in the 10−30 cm6/s range at room temperature, close to the larger theoretical calculations reported so far. However, a study of the combined effects of structural and model uncertainties suggests that the C values thus determined could be overestimated by about an order of magnitude. This preliminary attempt at uncertainty quantification confirms, beyond the present case, the need for an improved description of carrier transport and microscopic radiative and nonradiative recombination mechanisms in device-level LED numerical models

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Section: A Realistic Spatial Distribution Of Carriers In the Active mentioning

confidence: 90%

“…uncertainties in the valence band offset at the barrier/EBL interface. 45 Some effects of model and structural parameter variability will be addressed in Section V.…”

Section: D Simulation Studymentioning

confidence: 99%

Section: Auger Recombination and Auger-related Processesmentioning

confidence: 99%

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Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

et al. 2014

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“…The built-in interface charges due to spontaneous and piezoelectric polarization are calculated by methods developed by Fiorentini et al 18 50% of the theoretical value is used to account for the compensation by fixed defects and other interface charges. The AlGaN band offset ratio is assumed to be 50:50, according to the result of Piprek et al 19 We find that the simulation well number dependence in Ref. 20 can be reproduced only with a capture time constant of 1.0 × 10 −6 s, meaning that carriers can directly flow over the QWs with large probability.…”

mentioning

confidence: 88%

Optimal width of quantum well for reversed polarization blue InGaN light-emitting diodes

Kang

et al. 2013

AIP Advances

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The optical properties of reversed polarization (RP) blue InGaN light-emitting diodes (LEDs) under different quantum wells (QWs) width are numerically studied. We compared the band diagram, electron and hole concentration, emission wavelength, radiation recombination, internal quantum efficiency (IQE), turn on voltage and light output power (LOP) of these structures by numerical simulation. It found that QW width has a remarkable influence on the properties of RP blue InGaN LEDs. With the increase of QW width, the turn on voltage and radiation recombination rate decreases. It finds that the optimal width of QWs is about 3 nm at the current injection density of 15 A/cm2

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“…21 However, the leakage current is very sensitive to the properties of the electron blocking layer (EBL), especially the p-doping. 22 The sensitivity of leakage calculations to other AlGaN EBL parameter variations is illustrated in Fig. 3.…”

mentioning

confidence: 99%

III-Nitride LED efficiency droop models: A critical status review

Piprek¹

2013

2013 13th International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)

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-GaN-and AlN-based light-emitting diodes (LEDs) suffer from a severe efficiency reduction with increasing injection current (droop). Based on different theoretical models, several physical mechanisms have been proposed to explain the efficiency droop; however, conclusive experimental evidence is still missing for these proposals, and none of them is generally accepted. This presentation reviews and evaluates the main efficiency droop models currently under consideration.

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Electron leakage effects on GaN-based light-emitting diodes

Cited by 103 publications

References 20 publications

Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

Optimal width of quantum well for reversed polarization blue InGaN light-emitting diodes

III-Nitride LED efficiency droop models: A critical status review

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