Mercury telluride

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. The static and dynamic dielectric constants are 20.8 and 15.1, respectively. The thermal conductivity is low at 2.7 W·m2/(m·K). HgTe bonds are weak leading to low hardness values. The hardness is 2.7×107 kg/m2.

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.

Topological insulation

Main article: Topological insulator

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.

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.

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.

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

References

References

1. (2014). "Raman Spectroscopy of Optical Transitions and Vibrational Energies of ~1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes". ACS Nano.
2. (2016-08-12). "Strongly Confined HgTe 2D Nanoplatelets as Narrow Near-Infrared Emitters". Journal of the American Chemical Society.
3. Brice, J. and Capper, P. (eds.) (1987) ''Properties of mercury cadmium telluride'', EMIS datareview, INSPEC, IEE, London, UK.
4. Capper, P. (ed.) (1994) ''Properties of Narrow-Gap Cadmium-Based Compounds''. INSPEC, IEE, London, UK. {{ISBN. 0-85296-880-9
5. (1986). "Mercury selenide stoichiometry and phase relations in the mercury-selenium system". Journal of Solid State Chemistry.
6. (2007). "Quantum Spin Hall Insulator State in HgTe Quantum Wells". Science.