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

Abstract

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.

Characterization and photoluminescent enhancement of Li+ corporation effect on CaWO4:Eu3+ phosphor

“…As we all know, in a single white LED device, phosphor is one of the most indispensible materials in lighting technology, and thus it has been intensively investigated [3][4][5][6]. It is well known that a 450-470 nm blue-emitting diode excited yellow-emitting YAG:Ce 3+ phosphor has been widely used as the common white LED [7]. However, this kind of white light generated by blue chips with yellow phosphors has many disadvantages.…”

Optical and electrical characterization of AlGaInP solar cells

“…Despite its interesting features, little is known about AlGaInP as material for solar cells, although it has been widely used for the fabrication of other optoelectronic devices such as lasers and LEDs [5,6]. A deeper knowledge of the properties of AlGaInP as a function of aluminium concentration is therefore mandatory in order to enhance the efficiency of new generation multi-junction solar cells.…”

Preparation and its luminescent properties of AlPO4:Eu3+ phosphor for w-LED applications

“…Yttrium aluminum garnet doped with cerium (YAG:Ce) is commonly used as the yellow phosphor for this purpose. However, w-LEDs fabricated in this way give bi-chromatic white light with poor color quality (CRI ∼ 70) due to lack of red component [1,2]. One of the most promising approaches to generate white light in w-LEDs is to use a LED emitting near-UV light (UV-LED, 360-400 nm) coated with blue, green and red tri-color phosphors.…”