- Mercury(II) telluride
Mercury telluride (HgTe) is a binary chemical compound of mercury and
tellurium . It is asemi-metal related to the II-VI group ofsemiconductor materials. Alternative names are mercuric telluride and mercury (II) telluride.HgTe occurs in nature as the mineral form
coloradoite .Properties General Name mercury telluride Chemical Formula HgTe Appearance near black cubic crystals CAS number CASREF|CAS=12068-90-5 Structure Formula weight 328.19 u Lattice constant 0.646 nm Crystal structure zincblende Physical State of matter at STPsolid Melting point at SP943 K Boiling point at SP? Specific gravity 8.1 Electronic Band gap at 300 K−0.01 eV Electron effective mass 0.002 "m"e Light hole effective mass 0.002 "m"e Heavy hole effective mass 0.6 "m"e Electron mobility at 300 K15000 cm²/(V·s) Hole mobility at 300 K8000 cm²/(V·s) Precautions NFPA 704 Toxic red|YES
Decomposition products Highly toxic mercury and tellurium fumesSI units were used where possible.Properties
All properties are at standard temperature and pressure unless stated otherwise. The lattice parameter is about 0.646 nm in the cubic crystalline form. The bulk modulus is about 42.1 GPa. The thermal expansion coefficient is about 5.2×10−6/K. Static dielectric constant 20.8, dynamic dielectric constant 15.1. Thermal conductivity is low at 2.7W·m2/m·K. HgTe bonds are weak leading to low hardness values. Hardness 2.7×107 kg/m2.
Doping
n-type doping can be achieved with elements such as
boron ,aluminium ,gallium orindium . Iodine and iron will also dope n-type. HgTe is naturally p-type due to mercury vacancies. P-type doping is also achieved by introducing zinc, copper, silver or gold.Chemistry
HgTe bonds are weak. Their
enthalpy of formation , around −32kJ/mol, is less than a third of the value for the related compound cadmium telluride. HgTe is easily etched by acids, such ashydrobromic acid .Growth
Bulk growth is from a mercury and tellurium melt in the presence of a high mercury vapour pressure. HgTe can also be grown epitaxially, for example, by sputtering or by
metalorganic vapour phase epitaxy .ee also
*
coloradoite Related compounds
*
Cadmium telluride
*HgSe
*HgCdTe References
* Properties of mercury cadmium telluride, Ed. J. Brice and P. Capper, EMIS datareview, (INSPEC, IEE, London, UK, 1987).
* Properties of Narrow-Gap Cadmium-Based Compounds Ed. P. Capper (INSPEC, IEE, London, UK, 1994) ISBN 0-85296-880-9
* Tellurium and Tellurides, D. M. Chizhikov and V. P. Shchastlivyi, 1966, Nauka Publishing, Moscow
* Mercury selenide stoichiometry and phase relations in the mercury-selenium system, N. Z. Boctor and G. Kullerud, Journal of Solid State Chemistry Vol. 62, pp. 177-183 (1986) doi|10.1016/0022-4596(86)90229-X
* Total-energy study of the equation of state of HgTe and HgSe, Z. W. Lu, David Singh, and Henry Krakauer, Phys. Rev. B vol. 39, pp. 10154 (1989).External links
* [http://www.fiz-chemie.de/infotherm/html/molpages/03%5C06%5C/mol30632.html Thermophysical properties database] at Germany's Chemistry Information Centre, Berlin
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