Almaz Optics, Inc.
12 Chadsford Ct.  Marlton, NJ 08053, USA
Tel:  856 797-0491, Fax: 856 797-0228
e-mail: mail@almazoptics.com

 

SILICON Si

Silicon is commonly used as substrate material for infrared reflectors and windows in the 1.5 - 8 micron region. The strong absorption band at 9 microns makes it unsuitable for CO2 laser transmission applications, but it is frequently used for laser mirrors because of its high thermal conductivity and low density. Silicon is also useful as a transmitter in the 20 micron range. Maximum available size: 102 mm Dia x 50 mm Thk.

Main Properties

Chemical Formula Si
Molecular Weight 28.09
Crystal Class Cubic
Lattice Constant, Å 5.43
Density, g/cm3 at 293 K 2.329
Dielectric Constant for 9.37 x 109 Hz 13
Melting Point, K 1690
Thermal Conductivity, W/(m K)
at 125 K
at 313 K
at 400 K
598.6
163
105.1
Thermal Expansion, 1/K
at 75 K
at 293 K
at 1400 K
-0.5 x 10-6
2.6 x 10-6
4.6 x 10-6
Specific Heat, cal/(g K)
at 298 K
at 1800 K
0.18
0.253
Debye Temperature, K 640
Bandgap, eV 1.1
Solubility in water None
Knoop Hardness, kg/mm2 1100
Mohs Hardness 7
Young's Modulus, GPa 130.91
Shear Modulus, GPa 79.92
Bulk Modulus, GPa 101.97
Poisson's Ratio 0.28

Refractive Index

Wavelength, µm 1.40 1.50 1.66 1.82 2.05 2.50 3.50-5.00 6.00-25.00
Refractive Index 3.49 3.48 3.47 3.46 3.45 3.44 3.43 3.42

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