Arsenic(III) telluride
 | This This article is full of jargon, which irritates readers who are not experts. Some parts of this article look like a gibberish!may be too technical for most readers to understand.(November 2022) |
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3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.031.765 |
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PubChemCID
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CompTox Dashboard(EPA)
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| Properties | |
| As2Te3 | |
| Molar mass | 532.64g·mol−1 |
| Structure[1] | |
| Monoclinic | |
| C2/m | |
a= 14.339 Å,b= 4.006 Å,c= 9.873 Å α = 90°, β = 95°, γ = 90°
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| 564.96 | |
| 4 | |
| Hazards | |
| GHSlabelling: | |
 
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| Danger | |
| H301,H331,H410 | |
| P261,P264,P270,P271,P273,P301+P310,P304+P340,P311,P321,P330,P391,P403+P233,P405,P501 | |
| Related compounds | |
Otheranions
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Arsenic trioxide Arsenic trisulfide Arsenic triselenide |
Othercations
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Antimony telluride Bismuth telluride |
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).
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Arsenic(III) tellurideis aninorganic compoundwith thechemical formulaAs2Te3.It exists in two forms, themonoclinicα phase which transforms under high pressure to a rhombohedral β phase.[2]The compound is asemiconductor,with most current carried byholes.[3]Arsenic telluride has been examined for its use innonlinear optics.[4]
Molecular and crystal structure
[edit]Arsenic(III) telluride is a bulk form[clarification needed]ofgroup 15sesquichalcogenides[clarification needed]which form chains ofAs2Te3molecules that are eventually[clarification needed]stacked on top of each other and held together by weakVan der Waals forces.[5]This stacking of long branches ofAs2Te3molecules gives arsenic(III) telluride an amorphous crystalline[clarification needed]structure that can be found in the ɑ-As2Te3and β-As2Te3configurations at different pressures. Atambient pressure,ɑ-As2Te3yields a monoclinic structure with low thermoelectric properties; however, when placed in high pressure environments, ɑ-As2Te3transforms into the β-As2Te3configuration that has a rhombohedralR3mspace groupwith highthermoelectricproperties.[6][clarification needed]
As2Te3is a semiconductor and has been used to study nonlinear optics due to its ability to conduct electrical current; however, at high temperatures when doped with impurities[which?]causes these conductive abilities to transform irreversibly from its traditional semiconductor ability to metal conduction only.[5][7]This irreversible transformation is most likely caused by the doping materials added toAs2Te3forming impurity clusters which causes an increase inparamagnetictendency of the complex.[5][clarification needed]
Applications in nonlinear optics
[edit]As2Te3is the least studied amorphouschalcogenidecompound, which are a group of semiconductors primarily used innonlinear opticsas glasses or lenses to redistribute light.[8]It has not been studied widely due to the difficulty to synthesizeAs2Te3into amorphous crystalline solids. In order to avoid crystalizing arsenic telluride, it must be quenched quickly after it comes out of the melt.[8]Arsenic telluride andAs2Te3containing materials are starting to increase in popularity in the field ofnonlinear opticsbecause the amorphous glassesAs2Te3is exceptional at redistributing the electrical charge density of the light source (typically a laser) when it interacts within the medium.[9]The significance of this redistribution is that it allows for the modification of the laser’s nature to perform a specific function. Some examples of this are the use of lasers in sensors, optical communication systems, as well as changing the color of the laser for equipment and other machinery used in materials research.[6][7]
It has also been discovered in recent studies thatAs2Te3presents mobility edges, which are edges surrounding a conductive gap,[clarification needed]regardless of temperature allowing for the amorphous structure to conduct electricity at greater rates than expected.[8]Due to this, it can be hypothesized that the mobility edges lie betweendelocalizedandlocalizedstates as well as having a more energetically efficient transition from dark mobility tophotoconductivemobility than other amorphous glasses.[8]
Semiconductor
[edit]Arsenic(III) telluride, in its doped crystalline form, houses electron carriers that are caused by doping impurities that sit close to the edge due to the relatively free electron density around the edges.[10]These relatively free electrons interact with the impurities causing a decrease in electron density around the edge which causes a “tail” to form. These band tails overlap causing a gap or a hole, similar top-type doping,that can be used for conduction; however, the mobility of the carriers in the lattice decreases significantly near theFermi levelof the two tails.[7][10]This indicates that electronic stimuli, usuallyphononrelated, is needed to induce hopping of electrons into the gap to cause conduction.[5][10]The need of external phonon stimuli to cause electrical conductivity ofAs2Te3crystals further supports the effectiveness ofAs2Te3orAs2Te3based glasses in the use of nonlinear optics because the light upon entering the lattice causes the electron hopping inducing conduction. Since the electrons are hopping into the conductance gap near the Fermi level, the light is being modified and will exit the lattice in a different form than it entered.[10]
References
[edit]- ^Carron, G. J. (1963-05-01)."The crystal structure and powder data for arsenic telluride".Acta Crystallographica.16(5). International Union of Crystallography (IUCr): 338–343.doi:10.1107/s0365110x63000943.ISSN0365-110X.
- ^Sharma, Yamini; Srivastava, Pankaj (2011). "First principles investigation of electronic, optical and transport properties of α- and β-phase of arsenic telluride".Optical Materials.33(6). Elsevier BV: 899–904.Bibcode:2011OptMa..33..899S.doi:10.1016/j.optmat.2011.01.020.ISSN0925-3467.
- ^Moustakas, T. D.; Weiser, K. (1975-09-15). "Transport and recombination properties of amorphous arsenic telluride".Physical Review B.12(6). American Physical Society (APS): 2448–2454.Bibcode:1975PhRvB..12.2448M.doi:10.1103/physrevb.12.2448.ISSN0556-2805.
- ^Lee, Jinho; Jhon, Young In; Lee, Kyungtaek; Jhon, Young Min; Lee, Ju Han (2020-09-17)."Nonlinear optical properties of arsenic telluride and its use in ultrafast fiber lasers".Scientific Reports.10(1). Springer Science and Business Media LLC: 15305.Bibcode:2020NatSR..1015305L.doi:10.1038/s41598-020-72265-3.ISSN2045-2322.PMC7498598.PMID32943737.
- ^abcdBiswas, Shipra (2 April 1984). "Anomalous Electrical Resistance in Crystalline As2Te3".Department of Magnetism, Indian Association for the Cultivation of Science.
- ^abLee, Jinho; Jhon, Young In; Lee, Kyungtaek; Jhon, Young Min; Lee, Ju Han (2020-09-17)."Nonlinear optical properties of arsenic telluride and its use in ultrafast fiber lasers".Scientific Reports.10(1): 15305.Bibcode:2020NatSR..1015305L.doi:10.1038/s41598-020-72265-3.ISSN2045-2322.PMC7498598.PMID32943737.
- ^abcSegawa, Hideo (April 1974)."DC and AC Conductivity in Amorphous As2Se3-As2Te3System ".Journal of the Physical Society of Japan.36(4): 1087–1095.Bibcode:1974JPSJ...36.1087S.doi:10.1143/jpsj.36.1087.ISSN0031-9015.
- ^abcdWeiser, K.; Brodsky, M. H. (1970-01-15)."dc Conductivity, Optical Absorption, and Photoconductivity of Amorphous Arsenic Telluride Films".Physical Review B.1(2): 791–799.Bibcode:1970PhRvB...1..791W.doi:10.1103/physrevb.1.791.ISSN0556-2805.
- ^Kityk, I. V.; Kasperczyk, J.; Pluciński, K. (1999-10-01)."Two-photon absorption and photoinduced second-harmonic generation in Sb2Te3–CaCl2–PbCl2glasses ".Journal of the Optical Society of America B.16(10): 1719.doi:10.1364/josab.16.001719.ISSN0740-3224.
- ^abcdKrištofik, J.; Mareš, J. J.; Šmíd, V. (1985-05-16)."The Effect of Pressure on Conductivity and Permittivity of As2Te3-Based Glasses ".Physica Status Solidi A.89(1): 333–345.Bibcode:1985PSSAR..89..333K.doi:10.1002/pssa.2210890135.ISSN0031-8965.