Mercury telluride

Mercury Telluride. Compounds of mercury with tellurium have gained importance as semiconductors with appHcations in infrared detection (9) and solar cells (10). The ratio of the components is varied, and other elements such as cadmium, zinc, and indium are added to modify the electronic characteristics. 

Neumann-SpaUart M, Tamizhmani G, Boutry-ForveiUe A, Levy-Clement C (1989) Physical properties of electrochemicaUy deposited cadmium mercury telluride films. Thin Solid Eilms 169 315-322... 

W.F.H. Micklethwaite, The Crystal Growth of Cadmium Mercury Telluride Paul E. Petersen, Auger Recombination in Mercury Cadmium Telluride R.M. Broudy and V.J. Mazurczyck, (HgCd)Te Photoconductive Detectors M.B. Reine, A.K. Sood, and T.J. Tredwell, Photovoltaic Infrared Detectors M.A. Kinch, Metal-Insulator-Semiconductor Infrared Detectors... 

Camarero et al. [41] have prepared graded cadmium-mercury-telluride thin films (CdxFlgi cTe) applying cathodic electrodeposition at variable deposition voltage. Atomic proportions of mercury in the range 0.05-0.15 were considered. 

Mercury telluride (HgTe) was first made by vapour phase epitaxy in 1984. This preparation illustrates the use of ultraviolet radiation as the energy source for decomposition. Diethyltellurium ((C2H5)2Te) vapour in a stream of hydrogen carrier gas... 

In the preparation of lithium niobate by CVD, argon-containing oxygen is used as a carrier gas. In the preparation of mercury telluride, the carrier gas was hydrogen. Suggest reasons for these choices of carrier gas. 

The device may be formed by depositing alternating layers of cadmium telluride and mercury telluride by vapour phase deposition techniques and interdiffuse the layers, either during growth or subsequently, so as to form a mercury cadmium telluride layer. Reference is made to GB-A-2146663 (The Secretary of State for Defence, GB, 24.04.85) and GB-A-2203757 (Philips Electronic and Associated Industries Limited, GB, 26.10.88). 

Pyroelectric infrared detectors are inferior in detectivity by one or two orders of magnitude compared with photoconductors such as cadmium mercury telluride, as shown in Fig. 7.15. However, such materials require temperatures of 200 K for efficient operation and generally respond to rather narrow bands at the infrared wavelengths. Pyroelectric devices can discriminate temperature differences of 0.1 K but find many useful applications in which the discrimination is limited to about 0.5 K. They have the great practical advantage of operating at normal ambient temperatures. 

Triethylphosphane telluride formed mercury telluride when refluxed in toluene in the presence of elemental mercury, diethyl mercury, or diphenyl mercury1. Phosphane tellurides and methyl iodide in benzene under an inert atmosphere produce at room temperature methyltellurophosphonium iodides2. 

The compounds are soluble only in coordinating media. They are thermochromic, being red at room temperature and bright yellow at — 78°. In an evacuated, sealed tube at 120°, the compounds decompose to mercury telluride and diaryl tellurium3. 

W. F. H. Mickle thwaite, The Crystal Growth of Cadmium Mercury Telluride... 

The band gap decreases with increasing atomic number of the elements, so that materials such as cadmium mercury telluride Cd Hg/Te, in which a small proportion of the cadmium positions are taken by mercury, become conducting on exposure to infrared light and are used in heat seeking and night vision devices. 

A layered mercury telluride, Rb2Hg3Te4, was discovered during an exploration of hydro(solvo)thermal synthesis of tellurides at temperatures somewhat above the boiling... 

Bis[triethylgermyl] tellurium and mercury(II) chloride in tetrahydrofuran formed chloro-triethylgermane and mercury telluride. ... 

Neumann-Spallart M., Tamizhami G. and Levy-C16ment C. (1990), Photoelectro-chemical properties of semiconducting cadmium mercury telluride thin films with bandgap between 1.47 and 1.08 eV , J. Electrochem. Soc. 137, 3434-3437. 

Boron profiles by NDP in cadmium mercury telluride, an important infrared detector material, have been measured by Ryssel, et al. (31) and Vodopyanov, et al. (32). Cervena, et al. ( ) used NDP to study the implantation profiles of °B in several photoresists used in masking operations and to determine range values for Implants in several types of grown or deposited SIO2 films. 

Many other systems based on different nanoparticles have been introduced, such as copper indium disulfide (CuInS2) [263-265], copper indium diselenide (CuInSe2) [266,267], cadmium telluride (CdTe) [268], lead sulfide (PbS) [269,270], lead selenide (PdSe) [271], and mercury telluride (HgTe) [272]. Some of these systems show enhanced spectral response well into the infrared part of the solar spectrum [271,272]. In most cases the absorption of the nanocrystals was, however, quantitatively small as compared to the conjugated polymers. 

In this monograph, semiconductors and covalent or partially covalent insulators are considered. These materials differ from metals by the existence, at low temperature, of a fully occupied electronic band (the valence band or VB) separated by an energy gap or band gap (Eg) from an empty higher energy band (the conduction band or CB). When Eg reduces to zero, like in mercury telluride, the materials are called semimetals. In metals, the highest occupied band is only partially filled with electrons such that the electrons in this band can be accelerated by an electric field, however small it is. 

There is a problem with the widespread use of arsenic, cadmium, and selenium in electronic and photovoltaic devices. Cadmium mercury telluride is used in infrared-sensing night goggles. Cadmium sulfide, cadmium selenide, gallium arsenide, and analogues, are used in solar cells. If their use becomes widespread, then an efficient system of collecting used cells for reprocessing will be needed. Some workers feel that it will be better to use nontoxic silicon cells wherever possible. (Solar cells are discussed in Chap. 15.)... 

H3P04 PHOSPHORIC ACID 799 HgTe[g] MERCURY TELLURIDE (GAS) 835... 

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