Polycrystalline mercuric iodide detectors

Schieber, M.; Hermon, H.; Zuck, Asaf; Vilensky, A. I.; Melekhov, Leonid; Shatunovsky, Rubil; Meerson, E. E.; Saado, Y.

doi:10.1117/12.368177

Cited by 55 publications

(38 citation statements)

References 5 publications

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“…The result that the microcrystal grain size increases when the growth temperature increases was also found for films of the heavy metal iodides [5,7] and for other materials [25]. The grain sizes of lead bromide films are in the order, or smaller, than the ones of the heavy metal iodide films, which minimum values were 1 -5 µm for PbI 2 films [6] and 5-10 µm for mercuric iodide films [26].…”

Section: Resultsmentioning

confidence: 74%

Growth of lead bromide polycrystalline films

Giles

Cuña

Sasen

et al. 2004

Cryst. Res. Technol.

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Lead bromide polycrystalline films were grown by the physical vapor deposition method (PVD). Glass 1"x1" in size, uncoated, and coated with Indium Tin Oxide (ITO), was used as substrate and rear contact. The starting material was evaporated at temperatures from 395°C to 530°C under high vacuum atmosphere (6 x 10 -3 Pa) and during 8 days. The substrate temperature was prefixed from 190°C to 220°C. Film thickness yielded values from 40 to 90 µm. Optical microscopy and scanning electron microscopy (SEM) were performed on the films. Grain size resulted to be from 1.0 to 3.5 µm. SEM and X-ray diffraction indicate that films grow with a preferred orientation with the (0 0 l) planes parallel to the substrate. The Texture Coefficient (TC) related to the plane (0 0 6) was 7.3. Resistivity values in the order of 10 12 Ωcm were obtained for the oriented samples, but a strong polarization indicates severe charge transport problems in the films. Film properties were correlated with the growth temperature and with previous results for films of other halides.

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Section: Resultsmentioning

confidence: 74%

Growth of lead bromide polycrystalline films

Giles

Cuña

Sasen

et al. 2004

Cryst. Res. Technol.

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“…Mercuric iodide is used as a room-temperature X-and γ-ray detector [20,21] and HgBr x I 1-x has been investigated as a photodetector [22]. Acousto-optical devices containing mercury compounds are used in military, space, and commercial applications, including the detection of targets and of chemical and biological agents.…”

Section: Introductionmentioning

confidence: 99%

A solid-state 199Hg NMR study of mercury halides

Taylor

Bai

Dybowski

2011

Journal of Molecular Structure

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Abstract:The principal elements of the 199 Hg chemical-shift (CS) tensors of the mercuric halides (HgX 2 , X = F, Cl, Br, and I) and the mercurous halides (Hg 2 X 2 , X = F and Cl) were determined from spectra of static polycrystalline powders and from magic-angle spinning (MAS) spectra. The CS tensors of both HgCl 2 and Hg 2 Cl 2 are axially symmetric (η = 0) within experimental error, differing from literature reports of η=0.12 and η=0.14, respectively. The principal elements of the axially symmetric CS tensor in HgBr 2 were also measured using a static sample, and the wideline spectra of HgF 2 and HgI 2 (red polymorph) give chemical-shift tensors that suggest, within experimental error, that the mercury sits in sites of cubic symmetry. The 199 Hg CS tensor for Hg 2 F 2 is asymmetric.Experiments with static polycrystalline samples may allow the determination of the elements of the 199 Hg CS tensors even when MAS fails to completely average the dipolar coupling of the spin-½ 199 Hg and the quadrupolar halide nucleus.

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“…(Schieber et al 1999, Schieber et al 2001 PVD deposition was performed in a vacuum reactor where high purity HgI 2 powder was evaporated and deposited on arrays. The temperatures used during deposition were chosen based on a number of criteria, most importantly to encourage the c-axis of the crystal to grow perpendicularly to the array surface and to keep the temperature well below a value (~230° C) at which damage to the arrays would occur.…”

Section: Hgi 2 Fabricationmentioning

confidence: 99%

Signal behavior of polycrystalline HgI₂at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers

Antonuk

El‐Mohri

et al. 2008

Phys. Med. Biol.

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Active matrix, flat-panel x-ray imagers based on a-Si:H thin film transistors offer many advantages and are widely utilized in medical imaging applications. Unfortunately, the detective quantum efficiency (DQE) of conventional flat-panel imagers incorporating scintillators or a-Se photoconductors is significantly limited by their relatively modest signal to noise ratio, particularly in applications involving low x-ray exposures or high spatial resolution. For this reason, polycrystalline HgI 2 is of considerable interest by virtue of its low effective work function, high atomic number, and the possibility of large-area deposition. In this study, a detailed investigation of the properties of prototype, flat-panel arrays coated with two forms of this high-gain photoconductor are reported. Encouragingly, high x-ray sensitivity, low dark current, and spatial resolution close to the theoretical limits were observed from a number of prototypes. In addition, input-quantum-limited DQE performance was measured from one of the prototypes at relatively low exposures. However, high levels of charge trapping, lag, and polarization, as well as pixel-to-pixel variations in x-ray sensitivity are of concern. While the results of the current study are promising, further development will be required to realize prototypes exhibiting the characteristics necessary to allow practical implementation of this approach.

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Polycrystalline mercuric iodide detectors

Cited by 55 publications

References 5 publications

Growth of lead bromide polycrystalline films

Growth of lead bromide polycrystalline films

A solid-state 199Hg NMR study of mercury halides

Signal behavior of polycrystalline HgI₂at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers

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Polycrystalline mercuric iodide detectors

Cited by 55 publications

References 5 publications

Growth of lead bromide polycrystalline films

Growth of lead bromide polycrystalline films

A solid-state 199Hg NMR study of mercury halides

Signal behavior of polycrystalline HgI2at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers

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Product

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Signal behavior of polycrystalline HgI₂at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers