InGaN/GaN multiple-quantum-well light-emitting diodes with a grading InN composition suppressing the Auger recombination

Zhang, Zihui; Liu, Wei; Ju, Zhengang; Tan, Swee Tiam; Ji, Yun; Kyaw, Zabu; Zhang, Xueliang; Wang, Liancheng; Sun, Xiao Wei; Demir, Hilmi Volkan

doi:10.1063/1.4891334

Cited by 31 publications

(12 citation statements)

References 20 publications

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“…5, the carrier lifetime is 6.05, 4.66, 4.56 and 3.22 ns for LEDs with 3, 5, 8 and 11 QWs, respectively. The difference among these decay times under the low excitation power is mainly attributed to the different nonradiative recombination rates, which is ascribed to the SRH recombination rate since Auger recombination rate is minor under the low excitation level [21]. Therefore, the reduced carrier lifetime of LED devices with increasing QW number can be a solid support to the claim that in the practical growth a more serious defect-related SRH recombination would be induced in LED devices with more QWs.…”

Section: Resultssupporting

confidence: 50%

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Zhang¹,

Zhang²,

Liu³

et al. 2014

Opt. Express

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Abstract:In this work, InGaN/GaN light-emitting diodes (LEDs) possessing varied quantum well (QW) numbers were systematically investigated both numerically and experimentally. The numerical computations show that with the increased QW number, a reduced electron leakage can be achieved and hence the efficiency droop can be reduced when a constant Shockley-Read-Hall (SRH) nonradiative recombination lifetime is used for all the samples. However, the experimental results indicate that, though the efficiency droop is suppressed, the LED optical power is first improved and then degraded with the increasing QW number. The analysis of the measured external quantum efficiency (EQE) with the increasing current revealed that an increasingly dominant SRH nonradiative recombination is induced with more epitaxial QWs, which can be related to the defect generation due to the strain relaxation, especially when the effective thickness exceeds the critical thickness. These observations were further supported by the carrier lifetime measurement using a pico-second time-resolved photoluminescence (TRPL) system, which allowed for a revised numerical modeling with the different SRH lifetimes considered. This work provides useful guidelines on choosing the critical QW number when designing LED structures.

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Section: Resultssupporting

confidence: 50%

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Zhang¹,

Zhang²,

Liu³

et al. 2014

Opt. Express

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“…pol P(x) = ρ ∇ . In our setting, the equivalent negative polarization charge density is induced as Simon et al [26] and Zhang et al [27][28][29][30] suggested. And the polarization charge at the semipolar plane is changed as well due the induced of shear strain and projection angle [31,32].…”

Section: Resultsmentioning

confidence: 92%

Photoelectrochemical hydrogen generation with linear gradient Al composition dodecagon faceted AlGaN/n-GaN electrode

Lai¹,

Ma²,

Lin³

et al. 2014

Opt. Express

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We demonstrated photoelectrochemical cells (PECs) with dodecagon faceted AlGaN/n-GaN heterostructure electrode for H(2) generation, where the AlGaN/n-GaN heterostructure has a linear gradient Al composition (LGAC). The separation efficiency of the photo-generated electron-hole pairs in the electrode performs a key function in the H(2) generation efficiency of PEC cells. The linear gradient Al composition, AlGaN, could create more internal field and light absorption because of the linear graded band gap. Therefore, the zero-bias photocurrent density of PEC cells with dodecagon facet LGAC AlGaN/n-GaN heterostructure electrode is around 5.9 times larger than that of dodecagon faceted n-GaN electrode.

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“…We have also proposed a gradient InN composition in the quantum wells to suppress the Auger recombination for blue InGaN/GaN LEDs . Two blue InGaN/GaN LEDs are grown by the MOCVD technology and the peak emission wavelength for the two grown LEDs is ∼450 nm.…”

Section: Approaches For Improving the Internal Quantum Efficiencymentioning

confidence: 99%

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

Zhang

et al. 2016

Phys. Status Solidi A

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The internal quantum efficiency (IQE) for InGaN/GaN light‐emitting diodes (LEDs) grown on [0001] sapphire substrates is strongly affected by various factors including polarization effect in the InGaN/GaN multiple quantum wells (MQWs), insufficient electron and hole injections, low p‐type GaN doping efficiency, carrier loss due to the Auger recombination, and current crowding effect especially for the hole current in the p‐GaN region. In this work, the remedies taken by the scientific community to enhance the IQE are reviewed, compared and summarized. Meanwhile, this review also discusses alternative ways including polarization self‐screening effect, polarization cooling, hole accelerator, and hole modulator. The structural solutions we propose in this work can better improve the device performance without increasing the processing difficulty significantly, and their effectiveness in improving the IQE is further supported by the numerical and experimental studies. For example, on the contrary to common belief, the polarizations in the [0001] oriented InGaN/GaN LEDs can be advantageously used to improve the device performance based on our designs.

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InGaN/GaN multiple-quantum-well light-emitting diodes with a grading InN composition suppressing the Auger recombination

Cited by 31 publications

References 20 publications

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Photoelectrochemical hydrogen generation with linear gradient Al composition dodecagon faceted AlGaN/n-GaN electrode

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

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