Current-induced degradation and lifetime prediction of 310  nm ultraviolet light-emitting diodes

Ruschel, Jan; Glaab, Johannes; Beidoun, Batoul; Ploch, Neysha Lobo; Raß, Jens; Kolbe, Tim; Knauer, A.; Weyers, M.; Einfeldt, S.; Kneissl, Michael

doi:10.1364/prj.7.000b36

Cited by 57 publications

(45 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Before these measurements starts, incoming component inspection tests show at 0 h and 100 mA a similar voltage of (7.9 ± 0.3) V and an averaged wall plug efficiency of 0.79% and 0.63% for the investigated SQW and MQW LEDs, respectively. The development of the relative output power over the operation time is shown in Figure together with fits using the model described in the study by Ruschel et al [ 22 ] It can be seen that the L70 lifetimes (the time within which the output power drops to 70% of the initial value) is about 31 h for the TQW LEDs, but only 1 h for the SQW LED. It seems reasonable to attribute this difference to the different charge carrier distribution in the active region of these LEDs.…”

Section: Resultsmentioning

confidence: 99%

“…The symbols and error bars correspond to the mean values and the standard deviation of the mean from 15 nominally identical LEDs of each type. The solid lines are fits using the model described in the study by Ruschel et al [22] In a next step, the thickness of the SQW was increased to lower the charge carrier density in the well. LEDs with a 45 nm-thick lower QW barrier were used.…”

Section: Variations In the Active Region Of Sqw Ledsmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of Ultraviolet B Light‐Emitting Diodes with Single or Triple Quantum Wells

Kolbe

Knauer

Ruschel

et al. 2021

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

Light‐emitting diodes (LEDs) with an emission wavelength of 310 nm containing either a single or a triple quantum well are compared regarding their efficiency and long‐term stability. In addition, the influence of the thickness of the lower quantum well barrier and the quantum well thickness in single quantum well (SQW) LEDs is investigated. Electroluminescence measurements show a 28% higher initial output power for the SQW LEDs compared with the triple quantum well (TQW) LEDs because of larger spatial overlap of the carriers in the SQW as revealed by electro‐optical simulations of the LED heterostructures. However, TQW LEDs show a higher output power than SQW LEDs after 1 h operation under harsh conditions. For SQW LEDs, it is found that for a thicker lower quantum well barrier (65 nm instead of 25 nm) the initial output power decreases by ≈15%. A thicker SQW (3 nm instead of 1.6 nm) reduces the initial output power by even 45% but increases the lifetime by a factor of 6 which is attributed to reduced Auger recombination from an enhanced spatial separation of electrons and holes in the quantum wells due to the quantum‐confined Stark effect.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Variations In the Active Region Of Sqw Ledsmentioning

confidence: 99%

Comparison of Ultraviolet B Light‐Emitting Diodes with Single or Triple Quantum Wells

Kolbe

Knauer

Ruschel

et al. 2021

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

show abstract

“…Mie-scattering theory is used for the study of LaAsO4:Eu 3+ phosphor scattering effects and the computation of the scattering cross section Csca for spherical particles as expressed in the following expression [22,23]. Meanwhile, the Lambert-Beer law is used to compute the transmitted light power [24,25]:…”

Section: Resultsmentioning

confidence: 99%

Study of red-emitting LaAsO4:Eu3+ phosphor for color rendering index improvement of WLEDs with dual-layer remote phosphor geometry

2020

View full text Add to dashboard Cite

The remote phosphor structure is often disadvantageous in color quality but in terms of optics it is more convenient when compared to other phosphor structures such as conformal or in-cup ones. From this disadvantage, there are many studies to improve its chromatic output. In this research paper, we propose a dual-layer remote phosphor geometry for the improvement of white light-emitting diodes (WLEDs) in two parameters: color rendering index (CRI) and color quality scale (CQS). The 7700 K WLEDs are used in this study. The idea of the study is to place a red phosphor layer LaAsO4:Eu 3+ on the yellow phosphor YAG: Ce 3+ , and then find the concentration of LaAsO4:Eu 3+ in an appropriate way to achieve the highest color quality. The results showed that LaAsO4:Eu 3+ bring great benefits for enhancing CRI and CQS. In particular, the greater the concentration of LaAsO4:Eu 3+ , the greater the CRI and CQS because the portion of red lights in WLEDs increases. However, the decrease in lumen output occurs when the concentration of LaAsO4:Eu 3+ increases excessively. This is proved thanks to Mie-scattering theory and Beer-Lambert law. The results of important articles in WLEDs fabrication have greatly contributed to a higher white light quality

show abstract

“…Moreover, the scattering cross section of Csca for spherical particles are estimated with the support from the Mie theory. Furthermore, applying the Lambert-Beer law [24], [25] can help to compute the transmitted light power:…”

Section: Computation and Discussionmentioning

confidence: 99%

Improving the optical efficiency of white light-emitting diodes based on phosphor-in-glass by a dual-layer remote phosphorus structure with the application of LiLaO2:Eu3+ and CaSO4:Ce3+, Mn2+

Tien

2021

Bulletin EEI

View full text Add to dashboard Cite

While the remote phosphor structure is not an appropriate solution for WLED color uniformity, it is more advantageous for the luminous output of WLED than the conformal phosphor or in-cup phosphor structure. Acknowledging the ability of the remote phosphor structure, many studies have been carried out to surmount the color quality disadvantage of this structure. A dual-layer remote phosphor configuration is proposed in this research paper to acquire better color quality for WLEDs through heightening the color rendering index (CRI) and the color quality scale (CQS). The color temperature of the WLED packages this study is 8500 K. By inserting a layer of green CaSO4:Ce3+,Mn2+ or red LiLaO2:Eu3+ phosphor on the yellow YAG:Ce3+ phosphor layer, the phosphor structure configuration can be constructed. Then, to get the best color quality, the concentration of added phosphor LiLaO2:Eu3+ would be changed. The findings showed the rise of CRI and CQS along with the LiLaO2:Eu3+, which implies the influence of LiLaO2:Eu3+ to the growth of red light components within WLEDs packages. The greater the concentration of LiLaO2:Eu3+ is, the more the CRI and CQS increase. Meanwhile, the luminous flux gains from the green phosphor CaSO4:Ce3+,Mn2+. Nevertheless, the luminous flux and color quality would decrease if the concentrations of both red LiLaO2:Eu3+ and green CaSO4:Ce3+,Mn2+ phosphors reach a certain corresponding level. Centered on the Mie-scattering theory and the law of Lambert-Beer, this result is illustrated. The findings in this research are vital references for manufacturing WLEDs with higher white light performance.

show abstract

Current-induced degradation and lifetime prediction of 310 nm ultraviolet light-emitting diodes

Cited by 57 publications

References 31 publications

Comparison of Ultraviolet B Light‐Emitting Diodes with Single or Triple Quantum Wells

Comparison of Ultraviolet B Light‐Emitting Diodes with Single or Triple Quantum Wells

Study of red-emitting LaAsO4:Eu3+ phosphor for color rendering index improvement of WLEDs with dual-layer remote phosphor geometry

Improving the optical efficiency of white light-emitting diodes based on phosphor-in-glass by a dual-layer remote phosphorus structure with the application of LiLaO<sub>2</sub>:Eu<sup>3+</sup> and CaSO<sub>4</sub>:Ce<sup>3+</sup>, Mn<sup>2+</sup>

Contact Info

Product

Resources

About