Zinc selenide
Other names	Zinc selenide Stilleite
Identifiers
CAS number	1315-09-9 Y
PubChem	4298215
Properties
Molecular formula	ZnSe
Molar mass	144.35 g/mol
Appearance	light yellow solid
Density	5.27 g/cm3
Melting point	1525 °C
Solubility in water	negligible
Band gap	2.82 eV (25 ºC)
Refractive index (nD)	2.67 (550 nm) 2.40 (10.6 µm)
Structure
Crystal structure	Zincblende (cubic)
Lattice constant	a = 566.8 pm
Coordination geometry	Tetrahedral (Zn2+) Tetrahedral (Se2−)
Thermochemistry
Std enthalpy of formation ΔfHo298	−177.6 kJ/mol
Hazards
EU Index	034-002-00-8
EU classification	Toxic (T) Dangerous for the environment (N)
R-phrases	R23/25, R33, R50/53
S-phrases	(S1/2), S20/21, S28, S45, S60, S61
Related compounds
Other anions	Zinc oxide Zinc sulfide Zinc telluride
Other cations	Cadmium selenide Mercury selenide
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Zinc selenide (ZnSe), is a light yellow binary solid compound. It is an intrinsic semiconductor with a band gap of about 2.82 eV at 25 °C. ZnSe rarely occurs in nature. It is found in the mineral stilleite named after Hans Stille.

Contents 1 Applications 2 Chemistry 3 References 4 External links

[edit] Applications

• ZnSe is used to form II-VI light-emitting diodes and diode lasers. 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 introducing nitrogen.
• ZnSe doped with chromium (ZnSe:Cr) has been used as an infrared laser gain medium emitting at about 2.5 µm.^[1]
• It is used as an infrared optical material with a remarkably wide transmission wavelength range (0.45 µm to 21.5 µm^[2]). The refractive 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 µm 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 in spectroscopy or at the brewster angle, antireflection or beamsplitting coatings are generally employed.
• ZnSe doped with tellurium (ZnSe(Te)) is a scintillator with emission peak at 640 nm, suitable for matching with photodiodes. It is used in x-ray and gamma ray detectors. ZnSe scintillators are significantly different from the ZnS ones.

[edit] Chemistry

ZnSe reacts with acids to form toxic hydrogen selenide gas.

It is formed by chemical vapour deposition techniques including MOVPE.

[edit] References

1. ^ 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
2. ^ http://www.kayelaby.npl.co.uk/general_physics/2_5/2_5_8.html Kaye and Laby online at NPL

[edit] External links

• II-VI - INFRARED optical data & more
• University of Reading, Infrared Multilayer Laboratory optical data

v • d • e   Zinc compounds ZnBr2 · Zn(CN)2 · ZnCl2 · Zn(ClO3)2 · ZnCrO4 · ZnF2 · ZnH2 · ZnI2 · ZnMoO4 · Zn(NO3)2 · ZnO · ZnO2 · Zn(OH)2 · ZnS · ZnSO4 · ZnSb · ZnSe · ZnTe · Zn2P2O7 · Zn3As2 · Zn3N2 · Zn3P2 · Zn3(PO4)2