A Review on the Reliability of GaN-Based LEDs

Meneghini, Matteo; Trevisanello, Lorenzo Roberto; Meneghesso, G.; Zanoni, Enrico

doi:10.1109/tdmr.2008.921527

Cited by 247 publications

(122 citation statements)

References 24 publications

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“…Under a large current injection condition, electron concentration is approximate to hole concentration in the active region, and carrier concentration represents electron concentration or hole concentration [12]. Based on this ABC model, IQE-versus-n curve should be symmetry regarding to the peak IQE, which is different from the experimental asymmetry corresponding curve.…”

Section: Introductionmentioning

confidence: 99%

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

Zhao

Zhang

et al. 2015

J Sol State Light

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By modulating the indium composition in the quantum barriers of InGaN-based LEDs, the influence of electron distribution, electron overflow and Auger recombination on the external quantum efficiency (EQE) and droop effect have been investigated. Experimental results as well as numerical simulations reveal that the electron distribution is the key factor to influence both the peak efficiency and droop effect. The results show that the high electron concentration in the individual quantum well can stimulate the Auger recombination and lead to the droop effect instead of the total effective electron concentration, which is more related to the external quantum efficiency. If we modulate the indium composition in the quantum barriers of the InGaN-based LEDs, a uniform electron distribution can be achieved, which can not only enhance the EQE but also avoid the Auger recombination and improve the droop effect.

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Section: Introductionmentioning

confidence: 99%

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

Zhao

Zhang

et al. 2015

J Sol State Light

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“…While the decrease of both blue and yellow emission in the LEDs are related to both chip failure and phosphor degradation, the more pronounced reduction in blue over yellow intensity for the FC LEDs at 85% RH may indicate chip failure as a primary failure mechanism. In addition, the increase in series resistance RS at 85% RH (Table 1) compared to at 10% RH for both LEDs indicates degradation of the electrical properties of the devices due to increased resistivity of the contact and semiconductor material and to the degradation of the properties of the ohmic contacts [12].…”

Section: Resultsmentioning

confidence: 99%

Effects of humidity on the electro-optical-thermal characteristics of high-power LEDs

Law

Lim

et al. 2016

2016 IEEE 18th Electronics Packaging Technology Conference (EPTC)

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LEDs are subjected to environments with high moisture in many applications. In this paper, the experiments reveal photometric and colorimetric degradation at high humidity. Corresponding spectral power analysis and parameter extraction indicate that the flip-chip bonded LED samples show accelerated chip failure compared to the conventionally bonded samples. The chip-related failure induces greater heat accumulation, which correlates with the increase in heating power observed in the package. However, the temperature rise and thermal resistance for the flip-chip bonded LEDs do not increase substantially as compared to the conventionally bonded LEDs. This is because the junction temperature can be reduced with a flip-chip die-bonding configuration where the heat generated in the LED chip is dissipated effectively onto the AlN substrate, thereby reducing the increase in temperature rise and thermal resistance. The experimental results are supported by evaluation of the derivative structure functions. In addition, as the thermal resistance of the LED package varies with different humidity levels, there is a need to specify the conditions of humidity in data sheets as LED manufacturers routinely specify a universal thermal resistance value under a fixed operating condition.

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“…On the other hand, when the SRH nonradiative recombination is dominant, P approaches 2, which usually appears at low current. Therefore, the P values can show the influence of nonradiative defects in the active region [24][25][26][27]. Figure 10 A and decreased with the increase of the current.…”

Section: Analysis Of L-i Characteristicsmentioning

confidence: 95%

“…where P is the slope of the logarithmic plot of the L-I characteristic [24][25][26][27]. When the radiative recombination process is dominant, P is close to 1, which occurs at high current.…”

Section: Analysis Of L-i Characteristicsmentioning

confidence: 99%

Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

Kim¹,

Kim²,

Kim³

et al. 2015

Journal of the Optical Society of Korea

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A photoluminescence (PL) imaging method using a vision camera was employed to inspect InGaN/GaN quantum-well light-emitting diode (LED) epi-wafers. The PL image revealed dark spot defective regions (DSDRs) as well as a spatial map of integrated PL intensity of the epi-wafer. The Shockley-Read-Hall (SRH) nonradiative recombination coefficient increased with the size of the DSDRs. The high nonradiative recombination rates of the DSDRs resulted in degradation of the optical properties of the LED chips fabricated at the defective regions. Abnormal current-voltage characteristics with large forward leakages were also observed for LED chips with DSDRs, which could be due to parallel resistances bypassing the junction and/or tunneling through defects in the active region. It was found that the SRH nonradiative recombination process was dominant in the voltage range where the forward leakage by tunneling was observed. The results indicated that the DSDRs observed by PL imaging of LED epi-wafers were high density SRH nonradiative recombination centers which could affect the optical and electrical properties of the LED chips, and PL imaging can be an inspection method for evaluation of the epi-wafers and estimation of properties of the LED chips before fabrication.

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A Review on the Reliability of GaN-Based LEDs

Cited by 247 publications

References 24 publications

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

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

Effects of humidity on the electro-optical-thermal characteristics of high-power LEDs

Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

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