Mercury telluride

Mercury telluride
Names
Systematic IUPAC name
Mercury telluride
Other names
Mercuric telluride, mercury(II) telluride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.031.905
EC Number
  • 235-108-9
  • InChI=1S/Hg.Te
  • [Te]=[Hg]
Properties
HgTe
Molar mass 328.19 g/mol
Appearance near black cubic crystals
Density 8.1 g/cm3
Melting point 670°C
Structure
Sphalerite, cF8
F43m, No. 216
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Mercury telluride (HgTe) is a binary chemical compound of mercury and tellurium. It is a semi-metal related to the II-VI group of semiconductor materials. Alternative names are mercuric telluride and mercury(II) telluride.

HgTe occurs in nature as the mineral form coloradoite.

Physical 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 2.7 W·m2/(m·K). HgTe bonds are weak leading to low hardness values. Hardness 2.7×107 kg/m2.[1][2][3]

Doping

N-type doping can be achieved with elements such as boron, aluminium, gallium, or indium. 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.[1][2]

Topological insulation
Main article: Topological insulator
Electron micrograph (right) of a HgTe nanowire embedded in a carbon nanotube, combined with an image simulation (left).[4]

Mercury telluride was the first topological insulator discovered, in 2007. Topological insulators cannot support an electric current in the bulk, but electronic states confined to the surface can serve as charge carriers.[5]

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 as hydrobromic acid.[1][2]

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.[1][2]

Nanoparticles of mercury telluride can be obtained via cation exchange from cadmium telluride nanoplatelets.[6]

See also

References
  1. Brice, J. and Capper, P. (eds.) (1987) Properties of mercury cadmium telluride, EMIS datareview, INSPEC, IEE, London, UK.
  2. Capper, P. (ed.) (1994) Properties of Narrow-Gap Cadmium-Based Compounds. INSPEC, IEE, London, UK. ISBN 0-85296-880-9
  3. Boctor, N.Z.; Kullerud, G. (1986). "Mercury selenide stoichiometry and phase relations in the mercury-selenium system". Journal of Solid State Chemistry. 62 (2): 177. Bibcode:1986JSSCh..62..177B. doi:10.1016/0022-4596(86)90229-X.
  4. Spencer, Joseph; Nesbitt, John; Trewhitt, Harrison; Kashtiban, Reza; Bell, Gavin; Ivanov, Victor; Faulques, Eric; Smith, David (2014). "Raman Spectroscopy of Optical Transitions and Vibrational Energies of ~1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes" (PDF). ACS Nano. 8 (9): 9044–52. doi:10.1021/nn5023632. PMID 25163005.
  5. König, M; Wiedmann, S; Brüne, C; Roth, A; Buhmann, H; Molenkamp, L. W.; Qi, X. L.; Zhang, S. C. (2007). "Quantum Spin Hall Insulator State in HgTe Quantum Wells". Science. 318 (5851): 766–770. arXiv:0710.0582. Bibcode:2007Sci...318..766K. doi:10.1126/science.1148047. PMID 17885096. S2CID 8836690.
  6. Izquierdo, Eva; Robin, Adrien; Keuleyan, Sean; Lequeux, Nicolas; Lhuillier, Emmanuel; Ithurria, Sandrine (2016-08-12). "Strongly Confined HgTe 2D Nanoplatelets as Narrow Near-Infrared Emitters". Journal of the American Chemical Society. 138 (33): 10496–10501. doi:10.1021/jacs.6b04429. ISSN 0002-7863. PMID 27487074.
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