Influence of electron distribution on efficiency droop for GaN-based light emitting diodes

Fu, Jiajia; Zhao, Lixia; Zhang, Ning; Wang, Junxi; Li, Jinmin

doi:10.1186/s40539-015-0024-y

Cited by 6 publications

(4 citation statements)

References 29 publications

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“…Increasing bias voltage further is seen as efficiency roll‐off and device breakdown. The exact reason for efficiency roll‐off is beyond the scope of this paper; however, we speculate that it is due to nonradiative carrier loss mechanism at higher injection levels . We have also fabricated the device without PEIE and MoO 3 , but efficiency numbers are found to be much lower—it might be due to poor injection properties and morphological issues (see in Table S3 and Figures S5–S7, Supporting Information).…”

Section: Resultssupporting

confidence: 90%

Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters

et al. 2016

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This paper reports quantitative correlation of CH3NH3PbBr3 (MAPbBr3) thin film morphology to light emitting diode efficiency parameters. Sequential (spin coating) deposition is used for highly reproducible and dense film morphology of MAPbBr3 thin‐film. In this fabrication process using an orthogonal solvent approach, control of morphology, coverage, thickness, and optical properties in these compact thin‐films is demonstrated. Optical studies show direct correlation between morphology to dynamics of photoluminescence (PL) and absolute PL yield. Perovskite light emitting diodes (PeLEDs) are fabricated from these films to find the best ratio of PbBr2 versus MABr for optimal performance. This study demonstrates PeLEDs with high brightness, ≈1050 cd m−2 at 4.7 V (luminance efficiency ≈0.1 cd A−1), for optimal thin‐film process with state‐of‐the‐art device performance. This quantitative analysis suggests that these state‐of‐the‐art PeLEDs suffer from poor charge carrier balance (≈2%) and out‐coupling efficiency (≈6%). Interestingly, charge carrier balance and PL yield together can explain the change in PeLED efficiency modulation with film morphology. Studies on single carrier devices show that these PeLEDs are electron current dominated and charge carrier balance increases with operating bias voltage.

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Section: Resultssupporting

confidence: 90%

Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters

et al. 2016

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“…The light emissions are located at 455 nm, and except for the decreased intensity, there is no change in the peak wavelength. This indicates that there is no difference of the indium concentration in the multiple quantum wells 21 during the operation. Figure 3 shows the forward voltage at 350 mA for each sample measured at different stress intervals.…”

Section: Methodsmentioning

confidence: 91%

Degradation and corresponding failure mechanism for GaN-based LEDs

Zhao

Cao

et al. 2016

AIP Advances

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The degradation behaviors of high power GaN-based vertical blue LEDs on Si substrates were measured using in-situ accelerated life test. The results show that the dominant failure mechanism would be different during the operation. Besides that, the corresponding associated failure mechanisms were investigated systematically by using different analysis technologies, such as Scan Electron Microscopy, Reflectivity spectroscopy, Transient Thermal Analysis, Raman Spectra, etc. It is shown that initially, the failure modes were mainly originated from the semiconductor die and interconnect, while afterwards, the following serious deterioration of the radiant fluxes was attributed to the package. The interface material and quality, such as die attach and frame, play an important role in determining the thermal performance and reliability. In addition, the heating effect during the operation will also release the compressive strain in the chip. These findings will help to improve the reliability of GaN-based LEDs, especially for the LEDs with vertical structure.

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“…In addition, some researchers have studied the carrier distribution in the active region and its influence on the efficiency droop, and reported that the carrier distribution is a key factor affecting both the peak efficiency and efficiency droop. [8] To obtain high-efficiency GaN-based LEDs, many works have been carried out in optimizing GaN-based LEDs structures, and the use of AlGaN layers in GaN-based LEDs structures is a practical design method. Lin et al [9] reported that the inserted AlGaN layer between the n-type GaN layer and the InGaN active region can obtain higher peak efficiency and reduce efficiency droop at higher injection level.…”

Section: Introductionmentioning

confidence: 99%

Effect of AlGaN interlayer on luminous efficiency and reliability of GaN-based green LEDs on silicon substrate*

Guo¹,

Ding²,

Mo³

et al. 2020

Chinese Phys. B

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The effect of AlGaN interlayer in quantum barrier on the electroluminescence characteristics of GaN-based green light emitting diodes (LEDs) grown on silicon substrate was investigated. The results show that AlGaN interlayer is beneficial to improve the luminous efficiency of LED devices and restrain the phase separation of InGaN. The former is ascribed to the inserted AlGaN layers can play a key role in determining the carrier distribution and screening dislocations in the active region, and the latter is attributed to the increased compressive stress in the quantum well. However, when the electrical stress aging tests were performed at a current density of 100 A/cm2, LED devices with AlGaN interlayers are more likely to induce the generation/proliferation of defects in the active region under the effect of electrical stress, resulting in the reduced light output power at low current density.

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Influence of electron distribution on efficiency droop for GaN-based light emitting diodes

Cited by 6 publications

References 29 publications

Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters

Quantitative Correlation of Perovskite Film Morphology to Light Emitting Diodes Efficiency Parameters

Degradation and corresponding failure mechanism for GaN-based LEDs

Effect of AlGaN interlayer on luminous efficiency and reliability of GaN-based green LEDs on silicon substrate*

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