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Silicon (Si)

♦ Silicon (Si) Data Sheet    ♦ Silicon (Si) MSDS

Silicon is used as an optical window primarily in the 3 to 5 micron band and as a substrate for production of optical filters. Large blocks of Silicon with polished faces are also employed as neutron targets in Physics experiments.

Transmission Range :1.2 to 15 μm (1)
Refractive Index :3.4223 @ 5 μm (1) (2)
Reflection Loss :46.2% at 5 μm (2 surfaces)
Absorption Coefficient :0.01 cm-1 at 3 μm
Reststrahlen Peak :n/a
dn/dT :160 x 10-6 /°C (3)
dn/dμ = 0 :10.4 μm
Density :2.33 g/cc
Melting Point :1420 °C
Thermal Conductivity :163.3 W m-1 K-1 at 273 K
Thermal Expansion :2.6 x 10-6 / at 20°C
Hardness :Knoop 1150
Specific Heat Capacity :703 J Kg-1 K-1
Dielectric Constant :13 at 10 GHz
Youngs Modulus (E) :131 GPa (4)
Shear Modulus (G) :79.9 GPa (4)
Bulk Modulus (K) :102 GPa
Elastic Coefficients :C11=167; C12=65; C44=80 (4)
Apparent Elastic Limit :124.1MPa (18000 psi)
Poisson Ratio :0.266 (4)
Solubility :Insoluble in Water
Molecular Weight :28.09
Class/Structure :Cubic diamond, Fd3m

To download this data as a pdf file, or to download our MSDS safety data sheet, please click on the links at the top of the page.  To expand the transmission graphs, please click on the image.

Click to access current Silicon Stock Windows
Click to access current Silicon Stock ATR Prisms
Click to access current Silicon Stock Prisms 

µm   Noµm   Noµm   No
1.357   3.49751.367   3.49621.395   3.4929
1.5295   3.47951.660   3.46961.709   3.4664
1.813   3.46081.970   3.45372.153   3.4476
2.325   3.44302.714   3.43583.000   3.4320
3.303   3.4303.500   3.42844.000   3.4257
4.258   3.42454.500   3.42365.000   3.4223
5.500   3.42136.000   3.42026.500   3.4195
7.000   3.41897.500   3.41868.000   3.4184
8.500   3.418210.00   3.417910.50   3.4178
11.04   3.4176

Silicon is grown by Czochralski pulling techniques (CZ) and contains some oxygen which causes an absorption band at 9 microns. To avoid this, Silicon can be prepared by a Float-Zone (FZ) process. Optical Silicon is generally lightly doped ( 5 to 40 ohm cm) for best transmission above 10 microns. Silicon has a further pass band 30 to 100 microns which is effective only in very high resistivity uncompensated material. Doping is usually Boron (p-type) and Phosphorus (n-type).
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V1, ISBN 0-12-544420-6
(2) Li, Refractive Index of Germanium etc, J.Phys Chem, V9, p561, 1980
(3) Icenogle et al, Appl. Opt. V15, 2348 (1976)
(4) Wortman & Evans, V36, (1), P153 (1965)