The data on the composition of metacinnabar and Hg-sphalerite with an isomorphous Cd admixture from some mercury and complex ore objects are summarized. There are two varieties of metacinnabar: (1) cadmium-rich (9.25–15.80 wt.%), with the minimum quantity of Zn admixture (0.67–3.94 wt.%), which has the idealized formula (Hg,Cd,Zn)S (Ulandu) and (2) with increased amounts of Zn (2.21–10.83 wt.%) and Cd (6.00–14.10 wt.%), having the formula (Hg,Zn,Cd)S (Arzak, Kadyrel’, Murzinskoe, Ravnou-1, Ravnou-2). The maximum content of isomorphous Cd (15.80 wt.%) was determined in the metacinnabar from the Ulandu ore occurrence. The Hg-sphalerites are compositionally divided into two groups: (1) with an increased Cd concentration (up to 7.96 wt.%) and (2) mainly with a low content of Cd admixture (0.0n–1.63 wt.%). The sphalerites of the first group are typical of mineral assemblages including Cd-Zn-enriched metacinnabar (Arzak, Kadyrel’, Murzinskoe, Sarasa). The sphalerite of the Sarasa deposit is included into this group arbitrarily, because it contains more cadmium than the sphalerites of the second group, which are constituents of parageneses only with Zn-metacinnabar or lacking it (Nikitovka, Khaidarkan, Dzhizhikrut, Bayan-Khan, Aktash). There are some Hg-bearing varieties of sphalerite with the idealized formulas (Zn,Hg,Fe)S, (Zn,Hg,Cd)S, (Zn,Cd,Hg,Fe)S, (Zn,Fe,Cd,Hg)S, (Zn,Hg,Cd,Fe)S, (Zn,Fe,Hg,Cd)S, and (Zn,Hg,Cu)S, which transforms into (Zn,Cu,Hg)S. The maximum Cd admixture (7.96 wt.%) was established in Hg-sphalerite from the Kadyrel’ ore occurrence. It is the highest content observed in natural Hg-bearing β-ZnS. The studied metacinnabar and sphalerite varieties are the only cubic phases of the natural system Zn–Hg–Cd–S, which is sometimes expanded because of minor admixtures of other metals. These varieties have a structure identical to the cubic phases of the synthetic systems Me–S and Me–Me–S, where Me = Zn, Cd, and Hg. None of Hg-bearing hexagonal solid solutions were found in the natural system Zn–Hg–Cd–S. The continuity of the natural isomorphous series ZnScub–HgScub has not been confirmed by finding of natural intermediate solid solutions at the series fragment between (Zn0.752Hg0.248)S and (Hg0.539Zn0.461)S. The metacinnabar varieties enriched in both Zn and Cd show no correlation between these elements. It is assumed that the host rocks with an increased content of cadmium compounds were the source of Cd for the formation of specific varieties β-HgS and β-ZnS.

Ж у р н а л А с с о ц и а ц и и р е в м а т о л о г о в Р о с с и и. В ы х о д и т 6 р а з в г о д н а у ч н о-п р а к т и ч е с к а я Главный редактор Е.Л. Насонов-д.м.н., профессор, академик РАН,

Room temperature electroluminescence in the midinfrared near 4 m is reported from GaInAsSbP light emitting diodes grown on GaSb by liquid phase epitaxy. Comparison of the electro-and photoluminescence revealed that light is generated on the p side of the diode. The energy shift ͑24 meV͒ is consistent with band gap narrowing and recombination via band tail states due to the Zn doping ͑1 ϫ 10 18 cm −3 ͒ in the p layer of the structure. The temperature dependent behavior of the luminescence and the improved emission intensity was attributed to recombination from localized states arising from electrostatic potential fluctuations due to compositional inhomogeneities in these alloys. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2741147͔The realization of high emittance light emitting diodes ͑LEDs͒ and lasers for the midinfrared ͑2-5 m͒ spectral range, which can work efficiently at room temperature, is hampered by competing nonradiative Auger recombination and intervalence band absorption ͑IVBA͒. 1 This leads to poor internal efficiency in LEDs and high threshold currents in diode lasers. If suitable optoelectronic components could be made available one can envisage a wide variety of applications, including chemical process control, environmental monitoring of atmospheric pollution, and free space optical communications. One promising approach is to use the GaInAsPSb pentanary alloys because for a given value of the band gap ͑or lattice constant͒ properties such as the refractive index, spin-orbit valence band splitting ͑⌬ so ͒, or thermal expansion coefficient can be independently varied. 2,3 This offers a different approach to control optical confinement, carrier leakage, IVBA, and Auger recombination. However, although GaInAsPSb alloys have been grown, there has been very little work in this area. 4,5 Luminescence emission properties of broken gap GaInAsSbP / InAs isotype heterostructures and prototype light emitting diodes and photodiodes at short wavelengths ͑ Ͻ4 m͒ have been reported for alloys grown by liquid phase epitaxy ͑LPE͒ lattice matched onto InAs. 6,7 Recently, AlGaInAsSb alloys grown by molecular beam epitaxy have been effectively used as the barrier layers in room temperature midinfrared quantum well lasers. 8 In this letter the epitaxial growth of GaInAsPSb/ GaSb p-i-n structures from the liquid phase and a study of their electroluminescence properties are presented.Epitaxial growth of Ga 1−x In x As y P z Sb l-y-z single epilayers as well as p-i-n homostructures in which p-type layers were doped with Zn ͑1 ϫ 10 18 cm −3 ͒ and n-type layers were doped with Te ͑4 ϫ 10 17 cm −3 ͒ was carried out from antimony-rich melts onto Ge doped p-type GaSb ͑100͒ substrates. The use of antimony as the solvent for LPE growth of GaSb-related alloys has some advantages 9,10 compared with the more conventional techniques based on the low melting point metals, using In or Ga as solvents, namely, ͑1͒ Growth from Sb solution decreases the concentration of stoichiometric defects such as V Ga +Ga Sb , ͑2͒ etchback ...

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Computer modelling of a tandem TPV system has been carried out. The monolithic GaSb/lnSaAsSb tandem TPV devices have been designed and fabricated by LPE.