Dependence of Aging on Inhomogeneities in InGaN/AlGaN/GaN Light-Emitting Diodes

1999 ◽  
Vol 595 ◽  
Author(s):  
V.E. Kudryashov ◽  
S.S. Mamakin ◽  
A.N. Turkin ◽  
A.E. Yunovich ◽  
A.N. Kovalev ◽  
...  
Keyword(s):  
Space Charge ◽  
Quantum Efficiency ◽  
Space Charge Region ◽  
Radiation Intensity ◽  
Light Emitting Diodes ◽  
Reverse Current ◽  
Spectral Parameters ◽  
Light Emitting ◽  
Potential Fluctuations ◽  
Normal Currents

AbstractChanges of properties of green LEDs based on InxGa1-xN/AlyGa1-y/GaN heterostructures were studied during 150÷200 hours at currents J = 30÷80 mA. The radiation intensity at low currents (0.1÷1 mA) is quite sensitive to such an aging, it falls down 10÷100 times. Quantum efficiency and spectral parameters at normal currents (J ≈ 10 mA) change non-monotonically during aging, some degradation is observed after 168 hours. The degradation is observed also after a short (< 1 min) period of reverse current. These phenomena are discussed in terms of under threshold defect's formation and their migration in the space charge region of p-n-heterojunction. Potential fluctuations in the space charge region are quite sensitive to this process.

scholarly journals Dependence of aging on inhomogeneities in InGaN/AlGaN/GaN light-emitting diodes

2000 ◽  
Vol 5 (S1) ◽  
pp. 668-674
Author(s):  
V.E. Kudryashov ◽  
S.S. Mamakin ◽  
A.N. Turkin ◽  
A.E. Yunovich ◽  
A.N. Kovalev ◽  
...  
Keyword(s):  
Space Charge ◽  
Quantum Efficiency ◽  
Space Charge Region ◽  
Radiation Intensity ◽  
Light Emitting Diodes ◽  
Reverse Current ◽  
Spectral Parameters ◽  
Light Emitting ◽  
Potential Fluctuations ◽  
Normal Currents

Changes of properties of green LEDs based on InxGa1−xN/AlyGa1−y/GaN heterostructures were studied during 150÷200 hours at currents J = 30÷ 80 MA The radiation intensity at low currents (0.1÷1 mA) is quite sensitive to such an aging, it falls down 10÷100 times. Quantum efficiency and spectral parameters at normal currents (J ≈ 10 mA) change non-monotonically during aging, some degradation is observed after 168 hours. The degradation is observed also after a short (< 1 min) period of reverse current. These phenomena are discussed in terms of under threshold defect’s formation and their migration in the space charge region of p-n-heterojunction. Potential fluctuations in the space charge region are quite sensitive to this process.

scholarly journals Токовый шум и падение эффективности светодиодов при туннелировании носителей из квантовой ямы InGaN/GaN с участием дефектов

2019 ◽  
Vol 53 (1) ◽  
pp. 104
Author(s):  
Н.И. Бочкарева ◽  
А.М. Иванов ◽  
А.В. Клочков ◽  
Ю.Г. Шретер
Keyword(s):  
Space Charge ◽  
Quantum Wells ◽  
Quantum Efficiency ◽  
Space Charge Region ◽  
Noise Level ◽  
Efficiency Droop ◽  
Experimental Frequency ◽  
Light Emitting ◽  
Thermally Activated ◽  
Electric Field Direction

AbstractThe current dependences of the spectral noise density and quantum efficiency in green and blue light-emitting diodes with InGaN/GaN quantum wells (QWs) are measured. It is shown that the noise level greatly increases at high currents at which there is a quantum efficiency droop. The mechanism by which the current noise is formed is associated with hopping transport via the deep states of color centers in GaN across the n barrier of an InGaN/GaN QW. The source of the noise is the hopping resistance of the space-charge region, which limits the current of thermally activated electrons into the QW. The efficiency droop and the increase in noise level are attributed to a change in the electric-field direction near the QW at high injection levels and to an increase in the tunneling leakage of holes from the QW. It is shown that the experimental frequency-related noise spectra having the shape of a Lorentzian spectrum at the working currents are related to the frequency of hopping between deep centers near the InGaN/GaN QW and to Maxwell relaxation in the space-charge region.

Effect of Space Charge Region Width on Er-Related Luminescence in Reverse Biased Si:Er-Based Light Emitting Diodes

2006 ◽  
Vol 12 (6) ◽  
pp. 1556-1560 ◽  
Author(s):  
Viacheslav B. Shmagin ◽  
Sergey V. Obolensky ◽  
Dmitry Yu. Remizov ◽  
Viktor P. Kuznetsov ◽  
Zakhary F. Krasilnik
Keyword(s):  
Space Charge ◽  
Space Charge Region ◽  
Light Emitting Diodes ◽  
Light Emitting

scholarly journals Phenylalkylammonium passivation enables perovskite light emitting diodes with record high-radiance operational lifetime: the chain length matters

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuwei Guo ◽  
Sofia Apergi ◽  
Nan Li ◽  
Mengyu Chen ◽  
Chunyang Yin ◽  
...  
Keyword(s):  
Chain Length ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Surface Defects ◽  
Theoretical Modelling ◽  
Ion Migration ◽  
Light Emitting ◽  
Operational Lifetime ◽  
Chain Lengths

AbstractPerovskite light emitting diodes suffer from poor operational stability, exhibiting a rapid decay of external quantum efficiency within minutes to hours after turn-on. To address this issue, we explore surface treatment of perovskite films with phenylalkylammonium iodide molecules of varying alkyl chain lengths. Combining experimental characterization and theoretical modelling, we show that these molecules stabilize the perovskite through suppression of iodide ion migration. The stabilization effect is enhanced with increasing chain length due to the stronger binding of the molecules with the perovskite surface, as well as the increased steric hindrance to reconfiguration for accommodating ion migration. The passivation also reduces the surface defects, resulting in a high radiance and delayed roll-off of external quantum efficiency. Using the optimized passivation molecule, phenylpropylammonium iodide, we achieve devices with an efficiency of 17.5%, a radiance of 1282.8 W sr−1 m−2 and a record T50 half-lifetime of 130 h under 100 mA cm−2.

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

Perovskite Light‐Emitting Diodes with Near Unit Internal Quantum Efficiency at Low Temperatures

2021 ◽  
Vol 33 (14) ◽  
pp. 2006302
Author(s):  
Yarong He ◽  
Jiaxu Yan ◽  
Lei Xu ◽  
Bangmin Zhang ◽  
Qian Cheng ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Low Temperatures ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Light Emitting
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