Aluminium gallium indium phosphide (, also AlInGaP, InGaAlP, etc.) is a

semiconductor material A semiconductor is a material with electrical conductivity between that of a Electrical conductor, conductor and an Insulator (electricity), insulator. Its conductivity can be modified by adding impurities ("doping (semiconductor), doping") to ...

that provides a platform for the development of multi-junction photovoltaics and optoelectronic devices. It has a

direct Direct may refer to: Mathematics * Directed set, in order theory * Direct limit of (pre), sheaves * Direct sum of modules, a construction in abstract algebra which combines several vector spaces Computing * Direct access (disambiguation), ...

bandgap In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the ...

ranging from ultraviolet to infrared photon energies. AlGaInP is used in

heterostructure A heterojunction is an interface between two layers or regions of dissimilar semiconductors. These semiconducting materials have unequal band gaps as opposed to a homojunction. It is often advantageous to engineer the electronic energy bands in m ...

s for high-brightness red, orange, green, and yellow

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 (corre ...

s. It is also used to make

diode laser The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode p ...

Preparation

AlGaInP is typically grown by heteroepitaxy on

gallium arsenide Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...

gallium phosphide Gallium phosphide (GaP), a phosphide of gallium, is a compound semiconductor material with an indirect band gap of 2.24 eV at room temperature. Impure polycrystalline material has the appearance of pale orange or grayish pieces. Undoped single cr ...

substrates in order to form a

quantum well A quantum well is a potential well with only discrete energy values. The classic model used to demonstrate a quantum well is to confine particles, which were initially free to move in three dimensions, to two dimensions, by forcing them to occup ...

structure that can be fabricated into different devices.

Properties

The direct bandgap of AlGaInP encompasses the energy range of visible light (1.7 eV - 3.1 eV). By selecting a specific composition of AlGaInP, the bandgap can be selected to correspond to the energy of a specific wavelength of visible light. For instance, this can be used to obtain LEDs that emit red, orange, or yellow light. Like most other III-V semiconductors and their alloys, AlGaInP possesses a

zincblende crystal structure Sphalerite is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic mas ...

Applications

AlGaInP is used as the active material in: *Light emitting diodes of high brightness *Diode lasers *Quantum well structures *Solar cells (potential). The use of aluminium gallium indium phosphide with high aluminium content, in a five junction structure, can lead to solar cells with maximum theoretical efficiencies above 40%. AlGaInP is frequently used in LEDs for lighting systems, along with

indium gallium nitride Indium gallium nitride (InGaN, ) is a semiconductor material made of a mix of gallium nitride (GaN) and indium nitride (InN). It is a ternary group III/ group V direct bandgap semiconductor. Its bandgap can be tuned by varying the amount of ...

(InGaN).

Diode laser

A diode laser consists of a semiconductor material in which a p-n junction forms the active medium and optical feedback is typically provided by reflections at the device facets. AlGaInP diode lasers emit visible and near-infrared light with wavelengths of 0.63-0.76 μm. The primary applications of AlGaInP diode lasers are in optical disc readers, laser pointers, and gas sensors, as well as for

optical pumping Optical pumping is a process in which light is used to raise (or "pump") electrons from a lower energy level in an atom or molecule to a higher one. It is commonly used in laser construction to pump the active laser medium so as to achieve popu ...

, and machining.

Safety and toxicity aspects

The toxicology of AlGaInP has not been fully investigated. The dust is an irritant to skin, eyes and lungs. The environment, health and safety aspects of aluminium indium gallium phosphide sources (such as

trimethylgallium Trimethylgallium, often abbreviated to TMG or TMGa, is the organogallium compound with the formula Ga(CH3)3. It is a colorless, pyrophoric liquid. Unlike trimethylaluminium, TMG adopts a monomeric structure. When examined in detail, the monome ...

trimethylindium Trimethylindium, often abbreviated to TMI or TMIn, is the organoindium compound with the formula In(CH3)3. It is a colorless, pyrophoric solid. Unlike trimethylaluminium, but akin to trimethylgallium, TMI is monomeric. Preparation TMI is prepare ...

and

phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...

) and industrial hygiene monitoring studies of standard

MOVPE Metalorganic vapour-phase epitaxy (MOVPE), also known as organometallic vapour-phase epitaxy (OMVPE) or metalorganic chemical vapour deposition (MOCVD), is a chemical vapour deposition method used to produce single- or polycrystalline thin films. ...

sources have been reported in a review. Illumination by an AlGaInP laser was associated in one study with slower healing of skin wounds in laboratory rats.

References