Zinc telluride is a binary compound of zinc and tellurium with the chemical formula ZnTe. Zinc salt of telluric acid. Under normal conditions, it is a solid . A semiconductor , usually with a hole type of conductivity and a band gap of 2.23-2.25 eV .
| Zinc telluride | |
|---|---|
 A unit cell of crystals such as zinc blende. __ Zn __ Te | |
| Systematic name | Zinc telluride |
| Chemical formula | Znte |
| Appearance | red crystals |
| The properties | |
| Molar mass | 193.01 g / mol |
| Melting temperature | 1564 ± 2 K [1] ; 1238.5 ° C |
| Boiling temperature | decomp. |
| Density | 6.34 g / cm³ |
| Mohs hardness | 3-4 |
| Thermal conductivity | 0.18 W / (cm * deg) W / (mK) |
| Structure | |
| Crystal cell | cubic, such as zinc blende, lattice constant of 0.61 nm. Space group T 2 d -F43m |
| Coordination number | four |
| Molecule structure | tetrahedral |
| Thermodynamic properties | |
| Standard Enthalpy of Education | 109 [2] ; 126 [3] kJ / mol |
| Standard Gibbs formation energy | 92 [2] ; 79 [3] kJ / mol * K |
| Classification | |
| CAS Registration Number | 1315-11-3 |
| PubChem | 3362486 |
| Security | |
| NFPA 704 |  one 2 0 |
Properties
Physical Properties
It is a reddish-gray powder , after purification by sublimation - ruby- red crystals . The crystalline structure of the compound, stable under standard conditions , is cubic , with a crystal lattice such as zinc blende ( sphalerite ). Upon evaporation by powerful light radiation, in the presence of oxygen, ZnTe crystallizes in the form of hexagonal crystals of the wurtzite type. The lattice constant of the crystal structure of the sphalerite type is 0.61034 nm (the distance between Zn and Te atoms is 0.263 nm) and is close to the lattice constant of compounds such as aluminum antimonide , gallium antimonide, indium arsenide and lead (II) sulfide , which makes it possible to grow single-crystal low-dislocation ZnTe films on the substrates of these compounds, or, conversely, films of these compounds on a single-crystal ZnTe substrate. Some difficulties are posed by growing ZnTe films on a single crystal substrate of gallium arsenide due to the difference in lattice constants [5] . Also, polycrystalline ZnTe films with nanoscale crystals can be grown on glass substrates, for example, in the production of photovoltaic solar cells . In a wurtzite-type crystal structure, ZnTe has lattice constants a = b = 0.427 nm and c = 0.699 nm [6] [7] .
Chemical Properties
Insoluble in water. Reacts even with weak acids to produce hydrogen telluride :
In the gas phase at high temperature, it reversibly decomposes into elements, and Te in the gas phase is present mainly in the form of Te 2 molecules:
It is oxidized by oxygen, depending on the oxidation conditions to zinc oxide and elemental tellurium or to zinc oxide and tellurium dioxide :
Getting
It can be obtained in various ways:
- Synthesis of elements. It is produced by prolonged heating of a mixture of Zn and Te powders in a sealed quartz ampoule :
- The interaction of a soluble zinc salt in an aqueous solution with tellurium hydrogen:
- The exchange reaction of soluble telluride with a soluble zinc salt:
- The electrolytic method, while the anode is zinc and the cathode is telluric, in a solution of acid, for example, sulfuric .
Application
Optoelectronics
Since ZnTe is easily doped with acceptor impurities , it is a convenient material for use in optoelectronics . It is also used to create LEDs with blue radiation, semiconductor lasers , in solar cells and in microwave generators . In solar cells it can be used as a sublayer together with cadmium telluride. ZnTe, with p-type conductivity, is used in cadmium telluride – zinc telluride heterostructures [8] in pin diodes .
ZnTe is also a component of triple semiconductor compounds (forms a continuous series of solid solutions with a sphalerite structure with mercury telluride , zinc sulfide and cadmium telluride ). For example, cadmium-zinc telluride Cd x Zn (1-x) Te: at x = 0 corresponds to the ZnTe compound, at x = 1 to the CdTe compound. Changing the parameter x allows you to optimize the spectral optical characteristics when applied in optoelectronics.
Nonlinear Optics
ZnTe and lithium niobate are often used to generate terahertz electromagnetic pulses for studying the properties of substances by pulsed terahertz spectroscopy and radio wave non-destructive testing of dielectric parts with terahertz radiation . The generation of terahertz radiation in ZnTe crystals is excited by high-intensity pulses of light radiation and is caused by nonlinear optical effects that convert the energy of optical radiation into the energy of terahertz electromagnetic waves [9] . Conversely, irradiating a ZnTe single crystal with terahertz electromagnetic radiation causes a birefringence effect in it, which changes the polarization of transmitted light, which is suitable for creating terahertz radiation detectors.
Vanadium doped zinc telluride has another nonlinear optical property - to change its refractive index for optical radiation under the influence of light ( photorefraction ), which can be used to protect visible light receivers from its intense fluxes. Radiation limiters made of this material are light and compact, unlike complex optical limiters, and can be used as a protective tool for optical receivers from reversible “blinding” by an intense laser beam, which allows laser illumination to continue to be observed in poorly illuminated patterns. Zinc telluride can also be used in holographic interferometers in configurable optical networks and as electro-optical modulators for light flux switches . Compared to other semiconductors (types A [III] -B [V] or A [II] -B [VI]), ZnTe exhibits an exceptionally high photorefraction effect, and its doping with manganese significantly increases this effect.
Toxicity
It is considered a highly toxic substance, since when interacting with acids or hot water an extremely toxic tellurium is formed.
See also
- Cadmium Telluride
- Telluride Mercury
- Lead telluride
Notes
- ↑ Kulwicki BM - 'Ph. D. Thesis. ', Michigan, USA: Univ. of Michigan, 1963
- ↑ 1 2 Brebrick RF, Strauss AJ - J. Phis. Chem. Solids, 1964, 25, 144.
- ↑ 1 2 Rossini FD et. al. - Selected Values of Chemical Thermodynamic Properties. Cirk. of WBS, 500 US Departament of Commerce, WDS - 1952
- ↑ Kanazawa Ken , Yoshida Shoji , Shigekawa Hidemi , Kuroda Shinji. Dynamic probe of ZnTe (110) surface by scanning tunneling microscopy // Science and Technology of Advanced Materials. - 2015. - February 25 ( t. 16 , No. 1 ). - S. 015002 . - ISSN 1468-6996 . - DOI : 10.1088 / 1468-6996 / 16/1/015002 .
- ↑ Dakota O'Dell, MBE Growth and Characterization of ZnTe and Nitrogen-doped ZnTe on GaAs (100) Substrates , Department of Physics, University of Notre Dame, 2010
- ↑ Chemical Rubber Corporation, Handbook of Chemistry and Physics, 80th edition, 1999-2000, p. 12-98
- ↑ C. Kittel, Introduction to Solid State Physics, 5th edition (1976), p. 28.
- ↑ Nowshad Amin, Kamaruzzaman Sopian and Makoto Konagai, "Numerical modeling of CdS / CdTe and CdS / CdTe / ZnTe solar cells as a function of CdTe thickness," Solar Energy Materials and Solar Cells, Vol. 91, no. 13, 15 August 2007, pp 1202-1208
- ↑ THz Generation and Detection in ZnTe (inaccessible link) . Date of treatment December 15, 2012. Archived March 14, 2012.
Links
- National Compound Semiconductor Roadmap (Office of Naval research).
Literature
- Radautan S.I. , Turcan A.E. Zinc telluride. Chisinau: Shtiintsa, 1972.- 204 p.
- Hamdi, H., Valette, S. Journal of Applied Physics , Volume 51, issue 9 (September 1980), p. 4739-4741. ISSN : 0021-8979 DOI : 10.1063 / 1.328303
- Dinesh C. Sharma, Subodh Srivastava, YK Vijayl, YK Sharmal. Study of Optical Properties of Bilayer ZnTe: Al Film Grown on Glass Substrate by Thermal Evaporation Method. International Journal of Recent Research and Review, Vol. I, March 2012 ISSN 2277 - 8322.
- Bovina L.A. et al. Physics of Compounds AIIBVI / ed. A.N. Georgobiani, M.K.Sheinkman. - M.: Science, Ch. ed. Phys.-Math. lit., 1986. - 319, [1] p. : rice, table - 2600 copies.