- Zinc selenide
Chembox new
Name = Zinc selenide
ImageFile = Zinc-selenide-unit-cell-3D-balls.png
ImageName = Zinc selenide
OtherNames = zinc(II) selenide
Section1 = Chembox Identifiers
CASNo = 1315-09-9
Section2 = Chembox Properties
Formula = ZnSe
MolarMass = 144.35 g/mol
Appearance = light yellow solid
Density = 5.27 g/cm3, solid
Solubility = Insoluble
MeltingPt = 1525 °C
BoilingPt = °C
Section4 = Chembox Thermochemistry
DeltaHf = −177.6 kJ/mol
Entropy = ???? J.K−1.mol−1
Section7 = Chembox Hazards
ExternalMSDS = [http://physchem.ox.ac.uk/MSDS/ZI/zinc_selenide.html Oxford University Safety Data]
EUClass = Dangerous for
the environment (N)
RPhrases = R20 R22 R36 R38 R23/R25 R33
SPhrases =
Section8 = Chembox Related
OtherAnions =Zinc sulfide Zinc oxide Zinc telluride
OtherCations =Cadmium selenide Mercury selenide Zinc selenide (ZnSe), is a light yellow binary solid compound. It is an
intrinsic semiconductor with aband gap of about 2.7 eV at 25 °C. It has a standardenthalpy of formation of 177.6 kJ/mol at 25 °C. It adopts a zincblende lattice structure withlattice constant a=566.8picometer s.ZnSe rarely occurs in nature. It is found in the
mineral stilleite named afterHans Stille .Applications
* ZnSe is used to form II-VI
light-emitting diode s anddiode laser s. It emits blue light. It is susceptible to n-type doping with, for instance,halogen elements. P-type doping is more difficult, but can be achieved by introducingnitrogen .
* ZnSe doped withchromium (ZnSe:Cr) has been used as aninfrared laser gain medium emitting at about 2.5µm . [Cr2+ excitation levels in ZnSe and ZnS, G. Grebe, G. Roussos and H.-J. Schulz, J. Phys. C: Solid State Phys. vol. 9 pp. 4511-4516 (1976) doi|10.1088/0022-3719/9/24/020]
* It is used as an infrared optical material with a remarkably wide transmission wavelength range (0.6 µm to 20 µm). Therefractive index is about 2.67 at 550 nm (green), and about 2.40 at 10.6 µm (LWIR ). ZnSe is produced as microcrystalline sheets by synthesis from H2Se gas and zinc vapour. Lasertran (trademark of Rohm & Haas) grade is especially free of absorption and inclusions and is used particularly for CO2 laser optics at 10.6 micrometres wavelength. It is thus a very important IR material. In daily life, it can be found as the entrance optic in the new range of "in-ear" clinical thermometers and can be just seen as a small yellow window. Zinc selenide can slowly react with atmospheric moisture if poorly polished, but this is not generally a serious problem. Except where optics are use inspectroscopy or at thebrewster angle , antireflection or beamsplitting coatings are generally employed.
*Fragile, breaks easily.* ZnSe doped with
tellurium (ZnSe(Te)) is ascintillator with emission peak at 640 nm, suitable for matching withphotodiode s. It is used inx-ray andgamma ray detectors. ZnSe scintillators are significantly different from the ZnS ones.Chemistry
ZnSe reacts with acids to form toxic
hydrogen selenide gas.It is formed by
chemical vapour deposition techniques includingMOVPE .ee also
*
Zinc sulfide
*Zinc telluride
*Cadmium selenide
*Cadmium telluride References
External links
* [http://www.iiviinfrared.com/products/materials_znse.html II-VI - INFRARED] optical data & more
* [http://www.irfilters.reading.ac.uk/library/technical_data/infrared_materials/znse.htm Reading University] optical data
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