Improved Carrier Distributions by Varying Barrier Thickness for InGaN/GaN LEDs

Yu, Sheng-Fu; Lin, Ray–Ming; Chang, Shoou‐Jinn; Chen, J. R.; Chu, Jung‐Lien; Kuo, Cheng-Tzu; Zhang, Jiao

doi:10.1109/jdt.2012.2205367

Cited by 14 publications

(4 citation statements)

References 23 publications

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“…As reported, a thinner QB can reduce the strain to the QW, thus resulting in a smaller QCSE. 12 The smaller broadening magnitude of the FWHM in the GTQB LED is attributed to the reduced bandfilling effect benefiting from the improved carrier distribution in the InGaN/GaN QWs, as shown in Fig. 1.…”

mentioning

confidence: 90%

Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers

Liu

Zhang

et al. 2013

Applied Physics Letters

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Cataloged from PDF version of article.InGaN/GaN light-emitting diodes (LEDs) with graded-thickness quantum barriers (GTQB) are designed and grown by metal-organic chemical-vapor deposition. The proposed GTQB structure, in which the barrier thickness decreases from the n-GaN to p-GaN side, was found to lead to an improved uniformity in the hole distribution and thus, radiative recombination rates across the active region. Consequently, the efficiency droop was reduced to 28.4% at a current density of 70 A/cm2, which is much smaller than that of the conventional equal-thickness quantum barriers (ETQB) LED, which is 48.3%. Moreover, the light output power was enhanced from 770 mW for the ETQB LEDs to 870 mW for the GTQB LEDs at 70 A/cm2. © 2013 AIP Publishing LLC

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confidence: 90%

Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers

Liu

Zhang

et al. 2013

Applied Physics Letters

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“…We also found the EL intensity decrease with increasing LT-GaN cap layer thickness. It is known that a thicker GaN barrier layer (the total thickness of LT-GaN cap layer and HT-GaN QB) increases the distance of holes from p-GaN to the active region, resulting in a reduction in hole injection efficiency, which leads to a decrease in EL intensity [ 11 , 12 ]. In addition, the increase of In composition will enhance the piezoelectric field in InGaN QW layer, so that the energy band tilt is aggravated, resulting in a red-shift of peak emission and a reduced luminous efficiency, which is known as quantum-confined Stark effect (QCSE) [ 13 – 15 ].…”

Section: Resultsmentioning

confidence: 99%

Investigations on the Optical Properties of InGaN/GaN Multiple Quantum Wells with Varying GaN Cap Layer Thickness

et al. 2020

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Three InGaN/GaN MQWs samples with varying GaN cap layer thickness were grown by metalorganic chemical vapor deposition (MOCVD) to investigate the optical properties. We found that a thicker cap layer is more effective in preventing the evaporation of the In composition in the InGaN quantum well layer. Furthermore, the quantum-confined Stark effect (QCSE) is enhanced with increasing the thickness of GaN cap layer. In addition, compared with the electroluminescence measurement results, we focus on the difference of localization states and defects in three samples induced by various cap thickness to explain the anomalies in room temperature photoluminescence measurements. We found that too thin GaN cap layer will exacerbates the inhomogeneity of localization states in InGaN QW layer, and too thick GaN cap layer will generate more defects in GaN cap layer.

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“…The EL peak wavelength of LED II shifts by 1.9 nm with the current increasing from 2 to 5 mA while the peak wavelength of LED I shifts by 0.7 nm under the same current range. Generally, shifts of the EL peak wavelengths of InGaN/GaN MQWs LEDs upon increasing the injection current arise from two main reasons: 19) Figure 4 presents the EL peak wavelengths of LEDs I and II as of the injection current ranging from 2 to 50 mA. The dependence of the EL peak wavelength in the low current region is different from that in the high current region.…”

Section: Resultsmentioning

confidence: 99%

Effect of Si doping in barriers of InGaN/GaN multiple quantum wells on the performance of green light-emitting diodes

Lin

Hao

et al. 2015

Jpn. J. Appl. Phys.

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Green InGaN/GaN multiple quantum wells (MQWs) light-emitting diodes (LEDs) are of high In composition in well layers, a condition which results in large lattice mismatch between InGaN well layers and GaN barrier layers and hence boosts up the quantum-confined Stark effect (QCSE). Screening of the polarization electric fields within MQWs can effectively improve the internal quantum efficiency (IQE). This work investigates the effect of Si doping in barrier layers on the performance of green InGaN/GaN MQWs LEDs. It is revealed that a suitable doping density of Si (3.4 × 1016 cm−3) in barrier layers can promote the interfacial abruptness between the barrier and the well layers, reduce the In-composition fluctuation, and effectively screen the polarization electric fields. At the same time, suitable Si doping in barrier layers improves the lateral current spreading, alleviating the current crowding effect which is responsible for local heating and efficiency droop. However, overdoping of Si in barrier layers causes a series of negative effects, such as deteriorated interfacial quality and large current leakage. An effective approach for improving the performance of green LEDs is hence proposed.

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Improved Carrier Distributions by Varying Barrier Thickness for InGaN/GaN LEDs

Cited by 14 publications

References 23 publications

Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers

Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers

Investigations on the Optical Properties of InGaN/GaN Multiple Quantum Wells with Varying GaN Cap Layer Thickness

Effect of Si doping in barriers of InGaN/GaN multiple quantum wells on the performance of green light-emitting diodes

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