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Aluminium gallium arsenide

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(Redirected from AlGaAs) Semiconductor material
The crystal structure of aluminium gallium arsenide is zincblende.

Aluminium gallium arsenide (also gallium aluminium arsenide) (AlxGa1−xAs) is a semiconductor material with very nearly the same lattice constant as GaAs, but a larger bandgap. The x in the formula above is a number between 0 and 1 - this indicates an arbitrary alloy between GaAs and AlAs.

The chemical formula AlGaAs should be considered an abbreviated form of the above, rather than any particular ratio.

The bandgap varies between 1.42 eV (GaAs) and 2.16 eV (AlAs). For x < 0.4, the bandgap is direct.

The refractive index is related with the bandgap via the Kramers–Kronig relations and varies between 2.9 (x = 1) and 3.5 (x = 0). This allows the construction of Bragg mirrors used in VCSELs, RCLEDs, and substrate-transferred crystalline coatings.

Aluminium gallium arsenide is used as a barrier material in GaAs based heterostructure devices. The AlGaAs layer confines the electrons to a gallium arsenide region. An example of such a device is a quantum well infrared photodetector (QWIP).

It is commonly used in GaAs-based red- and near-infra-red-emitting (700–1100 nm) double-hetero-structure laser diodes.

Safety and toxicity aspects

The toxicology of AlGaAs has not been fully investigated. The dust is an irritant to skin, eyes and lungs. The environment, health and safety aspects of aluminium gallium arsenide sources (such as trimethylgallium and arsine) and industrial hygiene monitoring studies of standard MOVPE sources have been reported recently in a review.

References

  1. Shenai-Khatkhate, D. V.; Goyette, R. J.; DiCarlo, R. L. Jr.; Dripps, G. (2004). "Environment, Health and Safety Issues for Sources Used in MOVPE Growth of Compound Semiconductors". Journal of Crystal Growth. 272 (1–4): 816–821. Bibcode:2004JCrGr.272..816S. doi:10.1016/j.jcrysgro.2004.09.007.

External links

  • "AlxGa1−xAs". Ioffe Database. Sankt-Peterburg: FTI im. A. F. Ioffe, RAN.
Aluminium compounds
Al(I)
Organoaluminium(I) compoundsAl(C5(CH3)5)
Al(II)
Al(III)
Alums
Organoaluminium(III) compounds
Gallium compounds
Gallium(−V)
Gallium(I)
Gallium(II)
Gallium(I,III)
Gallium(III)
Organogallium(III) compounds
  • Ga(C5H7O2)3
  • Ga(CH3)3
  • Ga(C2H5)3
    • Arsenides
    Binary arsenides
    AsH3
    +H     		He
    LiAs Be BAs C +N +O F Ne
    Na3As Mg AlAs -Si P S +Cl Ar
    K CaAs Sc Ti V Cr MnAs Fe CoAs Ni Cu Zn3As2 GaAs -Ge As Se +Br Kr
    Rb Sr YAs Zr Nb MoAs2 Tc Ru Rh PdAs2 Ag Cd3As2 InAs -Sn Sb +Te +I Xe
    Cs Ba * Lu Hf TaAs WAs2 Re Os Ir Pt Au Hg Tl Pb BiAs Po At Rn
    Fr Ra ** Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
    ↓
    * La Ce PrAs Nd Pm SmAs Eu Gd Tb DyAs HoAs Er Tm Yb
    ** Ac Th Pa U NpAs
    NpAs2         		PuAs Am Cm Bk Cf Es Fm Md No
    Ternary arsenides
    Quaternary arsenides
    Quinary arsenides
    See also
    Categories: