Publication

GaN-based Single Mirror Light Emitting Diodes with high external quantum efficiency

Jean-François Carlin, Julien Dorsaz
2003
Journal Articles

Abstract

We present a study on the improvement of the external Quantum Efficiency (QE) of Gallium-Nitride-based Light Emitting Diodes (LEDs) by the use of the Single Mirror (SMLED) design [N.E.J. Hunt et al., Electron. Lett. 28, 2169 (1992)]. Three different substrate emitting LEDs are compared by measurements and simulations. An increase in the external QE by more than a factor of two is demonstrated, due to the enhancement of the Light Extraction Efficiency for the SMLED design. Using the SMLED design leads to values of the ext. QE of 10.9% (in air) and 23.2% (in glycerine, simulating a device in epoxy), while simulations predict Light Extraction Efficiencies (LEE) of 28% and 50% (in air and packaged) respectively, taking into account only the emission through the substrate. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhem.

Official source

https://infoscience.epfl.ch/entities/publication/c3b46713-f285-495f-9003-4a6284bef753

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Jean-François Carlin, Julien Dorsaz
2003
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/c3b46713-f285-495f-9003-4a6284bef753

About this result

Related concepts (25)

Light-emitting diode

A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

Quantum efficiency

The term quantum efficiency (QE) may apply to incident photon to converted electron (IPCE) ratio of a photosensitive device, or it may refer to the TMR effect of a Magnetic Tunnel Junction. This article deals with the term as a measurement of a device's electrical sensitivity to light. In a charge-coupled device (CCD) or other photodetector, it is the ratio between the number of charge carriers collected at either terminal and the number of photons hitting the device's photoreactive surface.

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.

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GaN-based Single Mirror Light Emitting Diodes with high external quantum efficiency

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