Identification of aging mechanisms in the optical and electrical characteristics of light-emitting diodes

Pursiainen, Otto L. J.; Linder, N.; Jaeger, A.; Oberschmid, R.; Streubel, K.

doi:10.1063/1.1413721

Cited by 88 publications

(49 citation statements)

References 8 publications

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“…It should be noted that an increase in the emission intensity similar to that observed in the present paper sometimes was observed during the first step of LED degradation test [17]. This also could be considered as an indication of similarity of processes taking place under the LEEBI and under forward current injection in GaN based LEDs.…”

Section: Methodssupporting

confidence: 58%

Effect of low energy electron irradiation on optical properties of InGaN/GaN light emitting structures

Вергелес

Shmidt

Yakimov

et al. 2011

Phys. Status Solidi (c)

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The effect of low energy e‐beam irradiation on the InGaN related cathodoluminescence in the MQW InGaN/GaN LED structures with different number of quantum wells has been studied. It is shown that the e‐beam exposure leads to an increase of emission intensity and to a formation of new blue‐shifted emission bands. It is shown that the changes in the optical properties are determined by the excess carrier injection. The changes observed were associated with the local changes of InGaN content due to In and/or Ga diffusion stimulated by the excess carrier recombination (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Methodssupporting

confidence: 58%

Effect of low energy electron irradiation on optical properties of InGaN/GaN light emitting structures

Вергелес

Shmidt

Yakimov

et al. 2011

Phys. Status Solidi (c)

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“…The L-I curve is traditionally divided into a nonlinear and a linear region. [46][47][48] The linear region is a result of the radiative recombination dominating in the active layer at a high bias voltage. In the nonlinear portion, the radiative intensity increases in roughly a quadratic manner as the forward bias current increases.…”

mentioning

confidence: 99%

Degradation mechanism beyond device self-heating in high power light-emitting diodes

Yung

Liem

Choy

et al. 2011

Journal of Applied Physics

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Temperature-dependence of the internal efficiency droop in GaN-based diodes Appl. Phys. Lett. 99, 181127 (2011) Localized surface plasmon-enhanced electroluminescence from ZnO-based heterojunction light-emitting diodes Appl. Phys. Lett. 99, 181116 (2011) Performance enhancement of blue light-emitting diodes with AlGaN barriers and a special designed electronblocking layer J. Appl. Phys. 110, 093104 (2011) A light emitting diode based photoelectrochemical screener for distributed combinatorial materials discovery Rev. Sci. Instrum. 82, 114101 (2011) Promotion of hole injection enabled by GaInN/GaN light-emitting triodes and its effect on the efficiency droop Appl. Phys. Lett. 99, 181115 (2011) Additional information on J. Appl. Phys. A unique degradation property of high power InGaN/GaN multiple quantum well (MQW) white light-emitting diodes (LEDs) was identified. The LEDs were stressed under different forwardcurrents. The various ageing characteristics were analyzed for both the electrical response and electro-luminescence (EL) spectra. The Raman spectroscopy allowed noninvasive probing of LED junction temperature profiles which correlated well with the EL characteristics, showing a junction temperature drop during degradation at certain current levels. In addition to the common observations: (1) a broadening of the light intensity-current (L-I) characteristic in the nonlinear regime, and (2) a shift of the current-voltage (I-V) dependence to higher current levels, the EL spectra showed different temperature responses of the two blue emission peaks, 440 and 463 nm. The former was temperature sensitive and thus related to shallow defect levels, while the latter was thermally stable and deeper defect states were involved in the degradation process. This unique selection rule resulted in the enhancement of the blue emission peak at 463 nm after degrading the LEDs. This study suggests that LED device heating is not directly linked to the degradation process.

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“…Aging is seen to result in a marginal variation of the I-V behaviour at sub-onset currents (δV F ∼ −5 mV at I F = 1 mA), which is probably due to the enhancement of nonradiative recombination and the emergence of ohmic shorts within the chip [6][7][8][9][10][11]. At the nominal current (350 mA), a remarkable drop in forward voltage (δV F = −70 mV) is observed.…”

Section: Resultsmentioning

confidence: 96%

“…Degradation of the output flux of LEDs received a lot of attention [2][3][4][5], although the background physical and materials' issues still require deeper understanding. Meanwhile, the effects of aging on electrical characteristics of LEDs are usually categorized as follows [6][7][8][9][10]: (i) an increase of sub-onset forward current due to an occurrence of additional nonradiative recombination routes, (ii) an increase of reverse current, and (iii) a decrease of forward current at nominal voltages mainly due to the deterioration of electrodes and contact layers. An increase of forward current in the entire range of voltages in aged InGaN LEDs was also observed and attributed to an occurrence of dislocation-related ohmic shorts within the chip [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of long-term aging on series resistance and junction conductivity of high-power InGaN light-emitting diodes

Vaitonis¹,

Miasojedovas²,

Novičkovas³

et al. 2009

Lithuanian J. Phys.

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The forward voltage, series resistance, and junction conductivity of commercial high-power InGaN light-emitting diodes (LEDs) were investigated as a function of aging time. A gradual decrease of series resistance with a rate of about −1%/1000 h was revealed in InGaN LEDs within first ∼9,600 hours of aging under ordinary conditions (nominal forward current 350 mA, junction temperature 350 K), whereas the characteristic energy of tunnel injection exhibited a decrease with a rate of about −0.1%/1000 h. The observed aging effects were attributed to continuous post-fabrication self-annealing of the p-type cladding layer and to the variation of the localized-state density in the active layer of the LED chips.

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Identification of aging mechanisms in the optical and electrical characteristics of light-emitting diodes

Abstract: Degradation mechanism beyond device self-heating in high power light-emitting diodes J. Appl. Phys. 109, 094509 (2011); 10.1063/1.3580264Optical studies of degradation of AlGaN quantum well based deep ultraviolet light emitting diodes

Cited by 88 publications

References 8 publications

Effect of low energy electron irradiation on optical properties of InGaN/GaN light emitting structures

Effect of low energy electron irradiation on optical properties of InGaN/GaN light emitting structures

Degradation mechanism beyond device self-heating in high power light-emitting diodes

Effect of long-term aging on series resistance and junction conductivity of high-power InGaN light-emitting diodes

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