Thick films of X-ray polycrystalline mercuric iodide detectors

Schieber, M.; Hermon, H.; Zuck, Asaf; Vilensky, A. I.; Melekhov, Leonid; Shatunovsky, Rubil; Meerson, E. E.; Saado, Y.; Lukach, M.; Pinkhasy, E.; Ready, S. E.; Street, R. A.

doi:10.1016/s0022-0248(01)00832-6

Cited by 91 publications

(60 citation statements)

References 8 publications

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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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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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“…The bulk crystalline phase has a melting point at 408 o C, a dielectric constant equal to 21, a mass density of 6.2 g/cm 3 and forbidden band gap of 2.34 eV. Its atomic number is Z Pb = 82 and Z I = 53 [8].…”

Section: Introductionmentioning

confidence: 99%

Stoichiometry, surface and structural characterization of lead iodide thin films

Condeles¹,

Lofrano²,

Rosolen³

et al. 2006

Braz. J. Phys.

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In this work we present the structural properties and stoichiometry analysis of thin films of lead iodide (PbI 2 ). This material is a very promising semiconductor material for the development of X-ray detectors in digital medical imaging. An alternative deposition method called Spray Pyrolysis was used. We discuss the main advantages and limitations of the deposition process comparing three different starting material powders. Extra iodine atmosphere during deposition and the effect of post-deposition thermal treatment is also discussed. The structural properties were studied by X-ray diffraction, Atomic Force Microscopy (AFM), Scanning Electronic Microscopy (SEM) and stoichiometry analysis were performed using Energy Dispersive Spectroscopy (EDS).

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“…HgI 2 films were previously obtained by physical vapor transport (PVT) and physical vapor deposition (PVD) [13][14]. In order to look for a cheaper fabrication process, we used the solvent evaporation technique, which was already used for crystals growth [1,15].…”

Section: Methodsmentioning

confidence: 99%

Growth of mercuric iodide crystals

et al. 2006

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Mercuric Iodide (HgI 2 ) is a semiconductor candidate for the construction of X-and gamma-ray detectors for digital medical imaging due to its high atomic number (Z Hg = 80, Z I = 53). Also, HgI 2 has a wide optical band-gap (2.13 eV) and high photon absorption coefficient for high-energy radiation. Different structures can lead to varying electrical and optical properties of the final material. In this work, HgI 2 crystals were produced by the solvent evaporation technique. The solvents used were ethanol (solubility around 20 mg/ml at 25 o C), ether (solubility around 3.5 mg/ml at 25 o C) and acetone (solubility around 24mg/ml at 25 o C). The evaporation conditions were varied in order to produce different final crystals. The Bérnard cells are responsible for crystallites formation due to the Bérnard-Maragoni convection in the liquid. Millimeter-sized crystals can be obtained as seen by Scanning Electron Microscopy.

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Thick films of X-ray polycrystalline mercuric iodide detectors

Cited by 91 publications

References 8 publications

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

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

Stoichiometry, surface and structural characterization of lead iodide thin films

Growth of mercuric iodide crystals

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Thick films of X-ray polycrystalline mercuric iodide detectors

Cited by 91 publications

References 8 publications

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

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

Stoichiometry, surface and structural characterization of lead iodide thin films

Growth of mercuric iodide crystals

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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

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