Measurement of the junction temperature in high-power light-emitting diodes from the high-energy wing of the electroluminescence band

Vaitonis, Z.; Vitta, P.; Žukauskas, A.

doi:10.1063/1.2908176

Cited by 44 publications

(31 citation statements)

References 46 publications

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“…39 This is the reason why we chose Philips LEDs for studying the degradation mechanism. The spectrum is reversible when the current is below 2100 mA, i.e., same features and intensities of the different emission bands are reserved for a specific current.…”

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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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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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“…During the measurement, the LEDs were mounted within an evacuated optical cryostat / oven (Cryo Industries model 110-637-DND). The temperature of the mount was maintained at 298 K with an accuracy better than 0.1 K. The overall uncertainty of the chip temperature in the I-V measurement estimated based on heat capacitance of sapphire was less than 1 K. However, the analysis of the high-energy wing of the electroluminescence spectra has indicated that an additional increase in junction temperature of up to 4 K is possible [14]. For the temperature coefficient of the forward voltage of −2 mV/K [13], this corresponds to the uncertainty of the forward voltage below 8 mV within the used range of the forward current and below 0.16 mV for the nominal current applied at different aging times (with the hereinafter estimated 2% drop of forward voltage due to aging and a corresponding reduction of Joule's heat taken into account).…”

Section: Methodsmentioning

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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“…In recent years, the development of semiconductor materials and thermal management of high-power LEDs have led to luminous efficacies higher than 276 lm/W [1]. The junction temperature of an LED has a large effect on the LED parameters such as forward voltage [2], spectrum [3], lifetime [4], maximum output power [5], and luminous efficacy [6]. The electrical power of the LEDs used e.g.…”

Section: Introductionmentioning

confidence: 99%

A temperature controller for high power light emitting diodes based on resistive heating and liquid cooling

Baumgartner

Vaskuri

Kärhä

et al. 2014

Applied Thermal Engineering

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Measurement of the junction temperature in high-power light-emitting diodes from the high-energy wing of the electroluminescence band

Cited by 44 publications

References 46 publications

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

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

A temperature controller for high power light emitting diodes based on resistive heating and liquid cooling

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