Gallium(II) selenide
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| Names | |
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IUPAC name
Gallium selenide
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| Other names
Gallium monoselenide
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| Identifiers | |
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3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.031.523 |
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PubChem CID
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| Properties | |
| GaSe | |
| Molar mass | 148.69 g/mol |
| Appearance | brown solid |
| Density | 5.03 g/cm3 |
| Melting point | 960 °C (1,760 °F; 1,230 K) |
| Band gap | 2.1 eV (indirect) |
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Refractive index (nD)
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2.6 |
| Structure | |
| hexagonal, hP8 | |
| P63/mmc, No. 194 | |
| Related compounds | |
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Other anions
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Gallium(II) oxide, Gallium(II) sulfide, Gallium(II) telluride |
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Other cations
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Zinc(II) selenide, Germanium monoselenide, Indium monoselenide |
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Related compounds
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Gallium(III) selenide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
Gallium(II) selenide (GaSe) is a chemical compound. It has a hexagonal layer structure, similar to that of GaS. It is a photoconductor, a second harmonic generation crystal in nonlinear optics, and has been used as a far-infrared conversion material at 14-31 THz and above.
It is said to have potential for optical applications but the exploitation of this potential has been limited by the ability to readily grow single crystals Gallium selenide crystals show great promise as a nonlinear optical material and . Non-linear optical materials are used in the frequency conversion of laser light. Frequency conversion involves the shifting of the wavelength of a monochromatic source of light, usually laser light, to a higher or lower wavelength of light that cannot be produced from a conventional laser source.
Several methods of frequency conversion using non-linear optical materials exist. Second harmonic generation leads to doubling of the frequency of infrared carbon dioxide lasers. In optical parametric generation, the wavelength of light is doubled. Near-infrared solid-state lasers are usually used in optical parametric generations.
One original problem with using gallium selenide in optics is that it is easily broken along cleavage lines and thus it can be hard to cut for practical application. It has been found, however, that doping the crystals with indium greatly enhances their structural strength and makes their application much more practical. There remain, however, difficulties with crystal growth that must be worked out before gallium selenide crystals may become more widely used in optics.
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