Recent progress of AlGaInP thin-film light-emitting diodes

Wirth, R.; Illek, S.; Karnutsch, Christian; Pietzonka, I.; Ploessl, Andreas; Stauß, P.; Stein, Wilhelm; Wegleiter, Walter; Windisch, Reiner; Zull, H.; Streubel, K.

doi:10.1117/12.476582

Cited by 10 publications

(2 citation statements)

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“…Compared to surface roughening, 13,14 our enhancement values are also lower. Surface roughening effectively scatters incident light randomly into all directions.…”

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confidence: 50%

Enhanced light extraction efficiency from AlGaInP thin-film light-emitting diodes with photonic crystals

Bergenek¹,

Wiesmann²,

Wirth³

et al. 2008

Applied Physics Letters

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We investigate the use of photonic crystals for light extraction from high-brightness thin-film AlGaInP light-emitting diodes with different etch depths, lattice constants, and two types of lattices (hexagonal and Archimedean). Both simulations and experimental results show that the extraction of high order modes with a low effective index neff is most efficient. The highest external quantum efficiency without encapsulation is 19% with an Archimedean A7 lattice with reciprocal lattice constant G=1.5k0, which is 47% better than an unstructured reference device.

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“…Compared to surface roughening, 13,14 our enhancement values are also lower. Surface roughening effectively scatters incident light randomly into all directions.…”

mentioning

confidence: 50%

Enhanced light extraction efficiency from AlGaInP thin-film light-emitting diodes with photonic crystals

Bergenek¹,

Wiesmann²,

Wirth³

et al. 2008

Applied Physics Letters

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“…AlGaInP is a direct-band-gap light-emitting quaternary material with a highly radiative recombination rate and a wide spectrum that ranges from yellow-green to red. 1,2) High-brightness AlGaInP light-emitting diodes (LEDs) have attracted increasing interest for applications such as in/ outdoor displays, traffic signals, and automobile indicators. [3][4][5] However, in the case of conventional heterojunction or multiple-quantum-well (MQW) AlGaInP LEDs on latticematched GaAs epitaxial growth substrates, however, due to a strong absorbing effect of GaAs material and the internal reflection, a requirement to reduce or (preferably) eliminate this negative effect is of great importance for the enhancement of light extraction efficiency.…”

Section: Introductionmentioning

confidence: 99%

High-Performance AlGaInP/GaAs Light-Emitting Diodes with a Carbon-Doped GaP/Indium–Tin Oxide Contact Layer

Hsu

Zheng

Horng

et al. 2008

jjap

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An alternative heavily carbon-doped GaP (GaP:C) contact layer is demonstrated to form a good ohmic contact to electronbeam-evaporation indium-tin oxide (ITO) spreading layer on the AlGaInP light-emitting diode (LED) with a GaAs absorbing substrate. The LEDs with GaP:C/ITO contact layer provide a substantial improvement in light output power over conventional structures (without GaP:C/ITO). The AlGaInP LEDs with GaP:C/ITO structures exhibited a higher external quantum efficiency (3.24%) and larger light output power (5.9 mW) under a dc operation of 160 mA than those of 2.01% and 1.93 mW at 120 mA for the conventional structures, showing an earlier saturation behavior of current-power characteristics. These positive results are tentatively attributed to the introduction of the GaP:C/ITO current-spreading structures in the LEDs.

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High-efficiency AlGaInP light-emitting diodes for solid-state lighting applications

Gessmann¹,

Schubert²

2004

Journal of Applied Physics

169

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AlGaInP lattice matched to GaAs is suited for light-emitting diodes ͑LEDs͒ operating in the red, orange, yellow, and yellow-green wavelength range. Such long-wavelength visible-spectrum devices will play an important role in solid-state lighting applications. This review discusses the major classes of AlGaInP device structures, including absorbing-substrate ͑AS͒ LEDs, absorbing substrate LEDs enhanced by distributed-Bragg-reflectors ͑DBRs͒, transparent substrate ͑TS͒ LEDs, thin-film ͑TF͒ LEDs, and LEDs using omnidirectional reflectors ͑ODRs͒. Some of these device structures have well-known deficiencies: A significant fraction of light is absorbed in the GaAs substrate in AS-LEDs; DBRs are essentially transparent at oblique angles of incidence leading to substantial optical losses. More recent developments such as TS-LEDs and TF-LEDs avoid these drawbacks. High-reflectivity, electrically conductive ODRs were recently developed that considerably outperform conventional distributed Bragg reflectors. LEDs using such conductive ODRs can replace DBRs in AlGaInP LEDs and are potential candidates for low-cost high-efficiency LEDs suitable for high-power solid-state lighting applications.

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Recent progress of AlGaInP thin-film light-emitting diodes

Cited by 10 publications

References 0 publications

Enhanced light extraction efficiency from AlGaInP thin-film light-emitting diodes with photonic crystals

Enhanced light extraction efficiency from AlGaInP thin-film light-emitting diodes with photonic crystals

High-Performance AlGaInP/GaAs Light-Emitting Diodes with a Carbon-Doped GaP/Indium–Tin Oxide Contact Layer

High-efficiency AlGaInP light-emitting diodes for solid-state lighting applications

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