Amorphous lead oxide (a-PbO): suppression of signal lag via engineering of the layer structure

Semeniuk, Oleksii; Grynko, Oleksandr; Juška, G.; Reznik, A.

doi:10.1038/s41598-017-13697-2

Cited by 19 publications

(17 citation statements)

References 45 publications

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“…Recently, we reported on the development of a new polymorphic form of the PbO material, namely amorphous Lead Oxide (a-PbO), which had not been previously synthesized 15 . In contrast to its polycrystalline counterpart, a-PbO is dense, capable of withstanding higher electric fields with lower dark current and exhibits no signal lag 16 . In this work, we use a-PbO in a bilayer PbO structure, where a thick layer of poly-PbO serves as a recording and charge transport layer while a thin layer of a-PbO acts as a lag-preventing layer.…”

Section: Scientific Reportsmentioning

confidence: 98%

Bilayer lead oxide X-ray photoconductor for lag-free operation

Grynko

Thibault

Pineau

et al. 2020

Sci Rep

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Polycrystalline Lead Oxide (poly-PbO) was considered one of the most promising photoconductors for the direct conversion X-ray medical imaging detectors due to its previous success in optical imaging, i.e., as an optical target in so-called Plumbicon video pick-up tubes. However, a signal lag which accompanies X-ray excitation, makes poly-PbO inapplicable as an X-ray-to-charge transducer in real-time X-ray imaging. In contrast, the recently synthesized Amorphous Lead Oxide (a-PbO) photoconductor is essentially lag-free. Here, we report on our approach to a PbO detector where a thin layer of a-PbO is combined with a thick layer of poly-PbO for lag-free operation. In the presented a-PbO/poly-PbO bilayer structure, the poly-PbO layer serves as an X-ray-to-charge transducer while the a-PbO acts as a lag prevention layer. The hole mobility in the a-PbO/poly-PbO bilayer structure was measured by photo-Charge Extraction by Linearly Increasing Voltage technique at different temperatures and electric fields to investigate charge transport properties. It was found that the hole mobility is similar to that in a-Se—currently the only commercially viable photoconductor for the direct conversion X-ray detectors. Evaluation of the X-ray temporal performance demonstrated complete suppression of signal lag, allowing operation of the a-PbO/poly-PbO detector in real-time imaging.

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Section: Scientific Reportsmentioning

confidence: 98%

Bilayer lead oxide X-ray photoconductor for lag-free operation

Grynko

Thibault

Pineau

et al. 2020

Sci Rep

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“…The requirement for a relatively low deposition temperature makes single-crystalline photoconductors unsuitable for use in direct conversion imaging detectors. As for the disordered (polycrystalline and amorphous), high-Z semiconductors that can produce large-area detectors, polycrystalline layers of PbI 2 [8][9][10], HgI 2 [10][11][12], CdTe [13], Cd 1-x Zn x Te [14], BiI 3 [15], ZnO [16], PbO [17,18], perovskites [19], and amorphous PbO (a-PbO) [20,21] are considered promising. However, at the current stage of their technology, the majority of the materials in this list exhibit signal lag-a residual current that continues to flow after X-ray exposure [17,18,22].…”

Section: Introductionmentioning

confidence: 99%

The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

Grynko

Thibault

Pineau

et al. 2021

Sensors

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The photoconductor layer is an important component of direct conversion flat panel X-ray imagers (FPXI); thus, it should be carefully selected to meet the requirements for the X-ray imaging detector, and its properties should be clearly understood to develop the most optimal detector design. Currently, amorphous selenium (a-Se) is the only photoconductor utilized in commercial direct conversion FPXIs for low-energy mammographic imaging, but it is not practically feasible for higher-energy diagnostic imaging. Amorphous lead oxide (a-PbO) photoconductor is considered as a replacement to a-Se in radiography, fluoroscopy, and tomosynthesis applications. In this work, we investigated the X-ray sensitivity of a-PbO, one of the most important parameters for X-ray photoconductors, and examined the underlying mechanisms responsible for charge generation and recombination. The X-ray sensitivity in terms of electron–hole pair creation energy, W±, was measured in a range of electric fields, X-ray energies, and exposure levels. W± decreases with the electric field and X-ray energy, saturating at 18–31 eV/ehp, depending on the energy of X-rays, but increases with the exposure rate. The peculiar dependencies of W± on these parameters lead to a conclusion that, at electric fields relevant to detector operation (~10 V/μm), the columnar recombination and the bulk recombination mechanisms interplay in the a-PbO photoconductor.

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“…Lead oxide (PbO) is a semiconductor of particular interest as considerable progress was achieved in its preparation and applications. PbO has been widely used in batteries [2], solar cells [3], gas sensors [4], photonics [5,6], radiation shielding materials [7,8], digital X-ray detectors [6][7][8][9]10], biomedical [7][8][9][10][11] and photocatalytic applications [12].…”

Section: Introductionmentioning

confidence: 99%

Annealing effect on the optical and photoelectrochemical properties of lead oxide

Zerguine

Abdi

Habelhames

et al. 2018

Eur. Phys. J. Appl. Phys.

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Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

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Amorphous lead oxide (a-PbO): suppression of signal lag via engineering of the layer structure

Cited by 19 publications

References 45 publications

Bilayer lead oxide X-ray photoconductor for lag-free operation

Bilayer lead oxide X-ray photoconductor for lag-free operation

The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

Annealing effect on the optical and photoelectrochemical properties of lead oxide

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