Mercury Cadmium Telluride

Mercury cadmium telluride , Hg _{1 − x} Cd _x Te ( English mercury cadmium telluride , MCT ) is a ternary semiconductor compound made from cadmium telluride and mercury telluride . It's a direct semiconductor .

Crystal structure

Crystal structure of Hg _{1 − x} Cd _x Te mixed with Hg and Cd in yellow, Te in white.

The entire series of mixtures Hg _{1 − x} Cd _x Te including the two edge phases HgTe and CdTe crystallizes in the zinc blende structure in space group F 4 3 m (space group no. 216) . Mercury and cadmium share a sublattice where they are statistically randomly distributed. The other sublattice consists entirely of tellurium . All atoms are coordinated tetrahedrally . Template: room group / 216

use

Band gap as a function of the cadmium content at different temperatures

Mercury cadmium telluride is used as a starting material for infrared sensors . One example of this is the high-resolution instrument of the Deep Impact spacecraft . The cadmium content in Hg _{1 − x} Cd _x Te determines the band gap and thus the wavelength sensitivity . Depending on the composition, the cut-off wavelength can thus be shifted. With 0% mercury (i.e. CdTe) the band gap is a maximum of 1.5 eV.

It was first synthesized in 1958 by a research group in England. Due to the linearity of the photo-electromagnetic effect on the magnetic field strength , thin-film sensors of this type can also be used for structurally simple magnetometers with a small time constant.

literature

P. Norton: HgCdTe infrared detectors . In: Opto-Electronics Review . tape 10 , no. 3 , 2002, p. 159-174 ( PDF ). ( Page no longer available ) Template: dead link /! ... nourl

Individual evidence

↑ WD Lawson, S. Nielsen, EH Putley, AS Young: Preparation and properties of HgTe and mixed crystals of HgTe-CdTe. In: Journal of Physics and Chemistry of Solids. 9, 1959, p. 325, doi : 10.1016 / 0022-3697 (59) 90110-6 .
↑ WD Lawson, S. Nielsen, EH Putley, AS Young: Preparation and properties of HgTe and mixed crystals of HgTe-CdTe . In: Journal of Physics and Chemistry of Solids . tape 9 , no. 3-4 , February 1959, pp. 325-329 , doi : 10.1016 / 0022-3697 (59) 90110-6 .
↑ Manfred von Ardenne: Effects of physics and their applications. 3rd edition Frankfurt am Main 2005, ISBN 978-3-8171-1682-9 .

[Lawson1959-1] WD Lawson, S. Nielsen, EH Putley, AS Young: Preparation and properties of HgTe and mixed crystals of HgTe-CdTe. In: Journal of Physics and Chemistry of Solids. 9, 1959, p. 325, doi : 10.1016 / 0022-3697 (59) 90110-6 .

[2] WD Lawson, S. Nielsen, EH Putley, AS Young: Preparation and properties of HgTe and mixed crystals of HgTe-CdTe . In: Journal of Physics and Chemistry of Solids . tape 9 , no. 3-4 , February 1959, pp. 325-329 , doi : 10.1016 / 0022-3697 (59) 90110-6 .

[3] Manfred von Ardenne: Effects of physics and their applications. 3rd edition Frankfurt am Main 2005, ISBN 978-3-8171-1682-9 .