The Equilibrium Partial Pressure of HgI2 over and Thermodynamic Properties of Hg3Te2I21)

Hutchins, Mark A.; Wiedemeier, H.

doi:10.1002/zaac.200500360

Cited by 4 publications

(6 citation statements)

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“…A typical vapor transport system consists of a closed silica tube with starting materials (HgQ and α-HgI 2 ) placed at one end as shown in Figure S1a. The equilibrium species in the gas phase at transport temperature presumably include Hg(g), Q n (g), and HgI 2 (g), I 2 (g), etc …”

Section: Resultsmentioning

confidence: 99%

“…Hg 3 Se 2 I 2 is isostructural with Hg 3 S 2 I 2 , with a = 9.7660(9) Å, b = 19.381(3) Å, and c = 9.6332(9) Å . Hg 3 Te 2 I 2 crystallizes into monoclinic crystal structure in space group C 2/ c , with a = 14.22(4) Å, b = 9.70(3), and c = 14.34(2) Å, β = 79.9(2)° . In addition, there is no phase transition of Hg 3 Se 2 I 2 in the range of ∼110–573 K …”

Section: Resultsmentioning

confidence: 99%

“…The powder X-ray diffraction (XRD) pattern in Figure S3 showed all samples are phase pure. In particular, Hg 3 S 2 I 2 crystallizes into orthorhombic structure in space group Imma, with a = 9.7992( 8 58 In addition, there is no phase transition of Hg 3 Se 2 I 2 in the range of ∼110−573 K. 38 The experimental bandgaps for Hg 3 Q 2 I 2 are 2.25, 2.12, and 1.93 eV, respectively, decreasing from S to Te (Figure 4d). The extension of the outermost s and p orbitals of the chalcogen atoms in the series S, Se, and Te accounts for the systematic decrease in the experimental band gap.…”

Section: ■ Experimental Sectionmentioning

confidence: 98%

“…According to partial pressure measurements of Hg 3 Te 2 I 2 , the most dominant of the gaseous species present are HgI 2 (g) and Hg(g). 58 Thus, it is reasonable to deduce that the major limitation of the vapor transport efficiency is the lower vapor pressure of chalcogens. The effect of additional iodine (I 2 ) as the transport agent was investigated.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…This method was very effective for Hg 3 Te 2 I 2 with 10−100 mg of excess I 2 during transport. By forming volatile tellurium iodides (such as TeI and TeI 4 58 ), Te atoms are effectively transported to the cold end where they are incorporated into the single crystalline Hg 3 Te 2 I 2 phase.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Defect Antiperovskite Compounds Hg₃Q₂I₂ (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection

Kontsevoi

Stoumpos

et al. 2017

J. Am. Chem. Soc.

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The high Z chalcohalides HgQI (Q = S, Se, and Te) can be regarded as of antiperovskite structure with ordered vacancies and are demonstrated to be very promising candidates for X- and γ-ray semiconductor detectors. Depending on Q, the ordering of the Hg vacancies in these defect antiperovskites varies and yields a rich family of distinct crystal structures ranging from zero-dimensional to three-dimensional, with a dramatic effect on the properties of each compound. All three HgQI compounds show very suitable optical, electrical, and good mechanical properties required for radiation detection at room temperature. These compounds possess a high density (>7 g/cm) and wide bandgaps (>1.9 eV), showing great stopping power for hard radiation and high intrinsic electrical resistivity, over 10 Ω cm. Large single crystals are grown using the vapor transport method, and each material shows excellent photo sensitivity under energetic photons. Detectors made from thin HgQI crystals show reasonable response under a series of radiation sources, including Am andCo radiation. The dimensionality of Hg-Q motifs (in terms of ordering patterns of Hg vacancies) has a strong influence on the conduction band structure, which gives the quasi one-dimensional HgSeI a more prominently dispersive conduction band structure and leads to a low electron effective mass (0.20 m). For HgSeI detectors, spectroscopic resolution is achieved for both Am α particles (5.49 MeV) andAm γ-rays (59.5 keV), with full widths at half-maximum (FWHM, in percentage) of 19% and 50%, respectively. The carrier mobility-lifetime μτ product for HgQI detectors is achieved as 10-10 cm/V. The electron mobility for HgSeI is estimated as 104 ± 12 cm/(V·s). On the basis of these results, HgSeI is the most promising for room-temperature radiation detection.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 98%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

See 3 more Smart Citations

Defect Antiperovskite Compounds Hg₃Q₂I₂ (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection

Kontsevoi

Stoumpos

et al. 2017

J. Am. Chem. Soc.

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The Equilibrium Partial Pressure of HgI₂ over and Thermodynamic Properties of Hg₃Te₂I₂.

Hutchins

Wiedemeier

2006

ChemInform

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Crystal Growth by Chemical Vapor Transport: Process Screening by Complementary Modeling and Experiment

Heinemann

Schmidt

2020

Crystal Growth & Design

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Despite chemical vapor transport (CVT) being a widely used method for crystal growth of inorganic substances, detailed mechanistic studies on the course of the crystallization process are rather few. In this study, an elaborated experimental screening run combined with sophisticated modeling of the respective heterogeneous equilibria is presented: Crystal growth of germanium by vapor transport with the addition of iodine has been chosen as a model system for validation of the applied method spectrum. In order to record the course and the interplay of heterogeneous equilibrium and nonequilibrium reactions in the system Ge−I, the experimental setup of high-temperature gasbalance (HTGB) is applied. Additionally, the observed evaporation processes are compared with saturation curves of corresponding volatile substances and, thus, can be assigned to individual species within the system. In this experimental screening, a phase sequence means to examine how the condensed phases undergo iodine depletion and how the gaseous phase undergoes a germanium enrichment when the temperature is increased. This phase screening combined with annealing experiments in the course of the phase sequence helps to analyze stepwise nonequilibrium products and to identify the characteristic species. Subsequently, for the evaluation of the composition of the gaseous phase, and for the deduction of the vapor transport mechanism, thermodynamic modeling by the CalPhaD method is performed. For the reference system, it is confirmed that iodine does not act as the transport agent. Instead, GeI 4 is responsible for the volatilization of germanium, forming GeI 2 . Nevertheless, investigations clearly illustrate how GeI 4 forms naturally in the phase sequence in the system Ge−I, which makes direct addition of it unnecessary. The recommended temperature range for vapor transport of germanium spans from 460 to 800 °C. Modeling shows that migration rates for germanium reaches a maximum at a mean temperature between 540 and 550 °C. Finally, vapor transport experiments were performed from 565 to 515 °C and from 690 to 590 °C. By increasing the deposition temperature, a slight decrease of the migration rate was observed, though a positive impact on the crystal's morphology was also found.

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The Equilibrium Partial Pressure of HgI₂ over and Thermodynamic Properties of Hg₃Te₂I₂¹⁾

Cited by 4 publications

References 20 publications

Defect Antiperovskite Compounds Hg₃Q₂I₂ (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection

Defect Antiperovskite Compounds Hg₃Q₂I₂ (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection

The Equilibrium Partial Pressure of HgI₂ over and Thermodynamic Properties of Hg₃Te₂I₂.

Crystal Growth by Chemical Vapor Transport: Process Screening by Complementary Modeling and Experiment

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The Equilibrium Partial Pressure of HgI2 over and Thermodynamic Properties of Hg3Te2I21)

Cited by 4 publications

References 20 publications

Defect Antiperovskite Compounds Hg3Q2I2 (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection

Defect Antiperovskite Compounds Hg3Q2I2 (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection