Vapor growth and characterization of pyrite (FeS2) doped with Co, Ni, and As: Variations in semiconducting properties

Lehner, S. W.; Savage, Kaye S.; Ayers, John C.

doi:10.1016/j.jcrysgro.2005.09.062

Cited by 100 publications

(76 citation statements)

References 29 publications

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“…In addition, the increase in As contents in pyrite expands the unit cell and creates structural distortion. Therefore, a combination of the electrical and crystalchemical properties of As may generate favorable conditions promoting the incorporation of heavy metals in pyrite in natural environments (Lehner et al 2006(Lehner et al , 2012. In the case of synthetic materials, it has been reported that p-type conductivity promotes high-solid solubility of Au in semiconductors matrices such as silicon (O'Shaughnessy et al 1974).…”

Section: And References Therein) Substitution Of As For S In the Tetmentioning

confidence: 99%

Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite

Deditius

Reich²

2016

American Mineralogist

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Arsenic-rich (arsenian) pyrite can contain up to tens of thousands of parts per million (ppm) of toxic heavy metals such as Hg, Tl, and Cd, although few data are available on their solid solubility behavior. When a compilation of Hg, Tl, and Cd analyses from different environments are plotted along with As in a M(Hg, Tl, and Cd)-As log-log space, the resulting wedge-shaped distribution of data points suggests that the solid solubility of the aforementioned metals is strongly dependent on the As concentration of pyrite. The solid solubility limits of Hg in arsenian pyrite-i.e., the upper limit of the wedge-shaped zone in compositional space-are similar to the one previously defined for Au by ), whereas the solubility limit of Tl in arsenian pyrite is approximated by a ratio of Tl/As = 1. In contrast, and despite a wedge-shaped distribution of Cd-As data points for pyrite in Cd-As log-log space, the majority of Cd analyses reflect the presence of mineral particles of Cd-rich sphalerite and/or CdS. Based on these data, we show that arsenian pyrite with M/As ratios above the solubility limit of Hg and Tl contain nanoparticles of HgS, and multimetallic Tl-Hg mineral nanoparticles. These results indicate that the uptake of Hg and Tl in pyrite is strongly dependent on As contents, as it has been previously documented for metals such as Au and Cu. Cadmium, on the other hand, follows a different behavior and its incorporation into the pyrite structure is most likely limited by the precipitation of Cd-rich nanoparticulate sphalerite. The distribution of metal concentrations below the solubility limit suggests that hydrothermal fluids from which pyrite precipitate are dominantly undersaturated with respect to species of Hg and Tl, favoring the incorporation of these metals into the pyrite structure as solid solution. In contrast, the formation of metallic aggregates of Hg and Tl or mineral nanoparticles in the pyrite matrix occurs when Hg and Tl locally oversaturate with respect to their solid phases at constant temperature. This process can be kinetically enhanced by high-to-medium temperature metamorphism and thermal processing or combustion, which demonstrates a retrograde solubility for these metals in pyrite.

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Section: And References Therein) Substitution Of As For S In the Tetmentioning

confidence: 99%

Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite

Deditius

Reich²

2016

American Mineralogist

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“…Semiconducting electrical properties such as resistivity, charge carrier concentration, and mobility are related to the type of impurity in pyrite (Bither et al, 1968;Chandler and Bene, 1973;Li et al, 1974;Zhao et al, 1993;Eyert et al, 1998;Lehner et al, 2006). We have studied the relationships among these electrical properties, impurity concentrations, and stoichiometry of synthetic pyrite doped with As, Co, and Ni and with negligible impurity (Lehner et al, 2006). From Hall effect measurements we found that resistivity, carrier concentration, and mobility vary predictably for pyrite with each type of impurity.…”

Section: Introductionmentioning

confidence: 99%

“…Holmes and Crundwell (2000) concluded that pyrite oxidation is an electrochemical reaction and that semiconducting properties of individual samples could have an influence on oxidation rates. Semiconducting electrical properties such as resistivity, charge carrier concentration, and mobility are related to the type of impurity in pyrite (Bither et al, 1968;Chandler and Bene, 1973;Li et al, 1974;Zhao et al, 1993;Eyert et al, 1998;Lehner et al, 2006). We have studied the relationships among these electrical properties, impurity concentrations, and stoichiometry of synthetic pyrite doped with As, Co, and Ni and with negligible impurity (Lehner et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

The effect of As, Co, and Ni impurities on pyrite oxidation kinetics: An electrochemical study of synthetic pyrite

Lehner

Savage

Ciobanu

et al. 2007

Geochimica et Cosmochimica Acta

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“…However, their transport properties such as carrier concentration, Hall mobility and resistivity exhibit large variations depending on the fabrication methods. 20,21,22,23,24,25,26,27 On the other hand, although p-type doping with P or As has been reported, the source of hole carriers is ambiguous due to the weak dependence of transport properties on the concentration of impurities, rather small Hall voltage, and large uncertainty caused by poor contacts. 21,22,24 A clear understanding of the key factors that govern the transport properties of pyrite is indispensable for solar energy conversion applications.…”

Section: Introductionmentioning

confidence: 99%

First-principles studies of the electronic properties of native and substitutional anionic defects in bulk iron pyrite

Zhang

Law

et al. 2012

Phys. Rev. B

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Abstract. Systematic spin-polarized density functional theory (DFT) calculations were performed to investigate the formation energies of native and substitutional anionic point defects in iron pyrite (FeS 2 ) and their impact on bulk electronic structure. A detailed analysis indicates that neutral sulfur and iron vacancies do not act as efficient donors or acceptors. We find that substitutional oxygen does not induce gap states in pyrite and can actually passivate gap states created by sulfur vacancies. Most group V and VII impurities create mid-gap states and produce spin polarization. In particular, Cl and Br are shallow donors that introduce delocalized spin-polarized electrons for potential use in photovoltaic and spintronics applications.

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Vapor growth and characterization of pyrite (FeS2) doped with Co, Ni, and As: Variations in semiconducting properties

Cited by 100 publications

References 29 publications

Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite

Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite

The effect of As, Co, and Ni impurities on pyrite oxidation kinetics: An electrochemical study of synthetic pyrite

First-principles studies of the electronic properties of native and substitutional anionic defects in bulk iron pyrite

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