Gallium Arsenide (GaAs)
Gallium Arsenide has specialist applications in far IR optics and lens systems.
 
Product Data -----------------------------------------------------
 
Transmission Range : 1 to 16 μm (1)
Refractive Index : 3.2727 @ 10.33 μm (1)
Reflection Loss : 44% @ 10.33 μm
Absorption Coefficient : 0.01 cm-1
Reststrahlen Peak : n/a
dn/dT : 147 x 10-6/°C @ 10  μm (4)
dn/dμ = 0 : 6.3 μm
Density : 5.315 g/cc
Melting Point : 1511°C
Thermal Conductivity : 48 W m-1 K-1 @ 273K (2)
Thermal Expansion : 5.7 x 10-6 /°C at 300K (3)
Hardness : Knoop 750
Specific Heat Capacity : 360 J Kg-1 K-1
Dielectric Constant : 12.91 at low frequencies
Youngs Modulus (E) : 84.8 GPa
Shear Modulus (G) : n/a
Bulk Modulus (K) : 75.5 GPa
Elastic Coefficients : n/a
Apparent Elastic Limit : 71.9 MPa
Poisson Ratio : 0.31
Solubility : Insoluble in water
Molecular Weight : 144.64
Class/Structure : Cubic ZnS, F43m, (100) cleavage
 
Refractive Index and Optical Transmittance curve----
Refractive Index(No = Ordinary Ray):
µm    No µm    No µm    No
1.033    3.492 1.550    3.3737 2.066    3.338
2.480    3.324 3.100    3.3125 4.133    3.3027
4.959    3.2978 6.199    3.2921 7.293    3.2874
8.266    3.2831 9.537    3.2769 10.33    3.2727
11.27    3.2671 12.40    3.2597 13.78    3.2493
15.50    3.2336 17.71    3.2081 19.07    3.1866
Optical Transmittance Curve of GaAs (Reference Data):
gallium-arsenide-gaas Transmittance
 
Special properties of GaAs-----------------------------------

It is nearly as hard ,strong and dense as Ge.

It is commmonly used in applications where toughness and durability are of great importance.

It has a low absorption coefficient of 0.01 cm-1 from 2.5 to 12 um

Its optical -grade material is generally more expensive than Ge and ZnSe.

GaAs is diamond turnable.

Typeical application: Thermal imaging, CO2 laser systems, FLIR.

Products manufactured:Lenses, Aspheric Lenses, Windows, Wedges.

Surface finish: Typical specifications for surface quality in the infrared are 40-20 or 60-40 scratch dig in the 2 to 7μm spectral region and 60-40, 80-50 or 120-80 scratch-dig for the 7-15μm area, depending upon system performance requirements.

Surface figure: In the infrared, typical surface figure ranges from 1/2 wave to 2 waves @0.6328 μm depending on the system performance requirements.

AR coating options: Typical available coatings for GaAs include a BBAR for 3 to 5μm spectral region, and a BBAR for the 8 to 12μm spectral region. Many other specialized bands are possible within the 2 to 15μm spectral region.
Product Notes:------------ --------------------------------------

Gallium Arsenide is produced by Czochralski or horizontal Bridgeman crystal growth techniques. As it is arsenic bearing, precautions in handling and working should be observed.

REFERENCES:
(1) Handbook Optical Constants, ed Palik, V1, ISBN 0-12-544420-6
(2) Deutch, J.Electron. Mater. V4 p679
(3) Sze, Physics of Semiconductor Devices, Wiley 1981
(4) M.Cadona. Proc. Int Conf. Semicond. Phys. 1960 p.388

Data provided is extracted from our technical handbook of materials. While every attempt has been made to verify the source of the information, ultiQuest Technology accept no responsibility for accuracy of data

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