Gallium(III) phosphide



Gallium(III) phosphide
IUPAC name Gallium(III) phosphide
Identifiers
CAS number 12063-98-8
Properties
Molecular formula GaP
Molar mass 100.7 g mol-1
Density 4.1 g/cm3
Melting point

1480 °C, 1753 K, 2696 °F

Hazards
EU classification (unknown)
NFPA 704
3
3
2
W
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Gallium phosphide (CAS number is [12063-98-8]. Multi-crystalline material has the appearance of pale orange pieces. Undoped single crystal wafers appear clear orange, but strongly doped wafers appear darker due to free-carrier absorption. It is odorless and insoluble in water.

n-type semiconductor. p-type semiconductor.

Gallium phosphide is also an optical material. Its refractive index is about 3.37 in the visible, but changes substantially with wavelength. At 800nm (IR) the index is lower, about 3.2.

Light-emitting diodes

Gallium phosphide is used for manufacture of low and standard brightness red, orange, and green gallium arsenide phosphide.

Pure GaP LEDs emit green light at a wavelength of 555 nm. zinc oxide doped GaP emits red (700 nm).

Gallium phosphide is transparent for yellow and red light, therefore GaAsP-on-GaP LEDs are more efficient than GaAsP-on-GaAs.

At temperatures above ~900C Gallium Phosphide dissociates and the phosphorus escapes as a gas. To grow a crystal from a 1500C melt (for LED wafers), this must be prevented by holding the phosphorus in with a blanket of molten Boric Oxide plus surrounding inert gas pressure of 10-100 atmospheres. The process is called Liquid Encapsulated Czochralski growth (typically abbreviated "LEC"), an elaboration of the Czochralski process used for Silicon wafers.

See also

Related materials

Alloys
 
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