Electron–hole pair creation energy in amorphous selenium for high energy photon excitation

Hijazi, Nour; Panneerselvam, Dhilippan M.; Kabir, Md. Tanvir

doi:10.1007/s10854-017-7937-8

Cited by 12 publications

(4 citation statements)

References 17 publications

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“…The rate of energy deposition by a primary electron (i.e., stopping power) decreases with its kinetics energy and so does with photon energy (see Table 1 and [68]). Thus, the density of ehps in the column decreases with increasing photon energy and ehps have a greater probability of escape [34,35,40,41,54]. Therefore, with…”

Section: Appendix B Model For the Charge Generation And Recombination Processes In A-pbomentioning

confidence: 99%

“…To the best of our knowledge, the only photoconductor whose X-ray energy dependency on W ± has been examined (both experimentally [31,41,[50][51][52] and theoretically [34,35,37,[53][54][55]) is a-Se. As was discussed in [34] (and references therein), within the framework of the geminate recombination model, the initial separation between an electron and a hole controls the probability of their escape from recombination.…”

Section: X-ray Energy Dependencymentioning

confidence: 99%

“…As for the recombination, there are three main theories that could explain the loss of the X-ray-generated carriers in the photoconductors: the bulk (Langevin), geminate (Onsager), and columnar (track) models [32][33][34][35][36][37][38][39][40][41]. Bulk Langevin recombination is a bimolecular process in which electrons and holes drift through the bulk of the photoconductor, due to the internal electric field within the layer, meet each other in space and time, and recombine.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Appendix B Model For the Charge Generation And Recombination Processes In A-pbomentioning

confidence: 99%

Section: X-ray Energy Dependencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

Grynko

Thibault

Pineau

et al. 2021

Sensors

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“…Amorphous selenium (a-Se) has been widely used for X-ray optoelectronic devices due to its excellent X-radiation responsive properties [1,2,3]. The thermal evaporation method is a good way to prepare a-Se films [4,5,6], and the background vacuum operating 10 −3 Pa to 10 −4 Pa is a current preparation condition [7,8,9].…”

Section: Introductionmentioning

confidence: 99%

Investigations on Structural, Optical and X-Radiation Responsive Properties of a-Se Thin Films Fabricated by Thermal Evaporation Method at Low Vacuum Degree

Zhu

Yang

et al. 2018

Materials

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Amorphous selenium (a-Se) thin films with a thickness of 1200 nm were successfully fabricated by thermal evaporation at a low vacuum degree of 10−2 Pa. The structural properties involving phase and morphology showed that a-Se thin films could be resistant to 60 °C in air. Also, a transformation to polycrystalline Selenium (p-Se) was shown as the annealing temperature rose to 62 °C and 65 °C, with obvious changes in color and surface morphology. Moreover, as the a-Se transformed to p-Se, the samples’ transmittance decreased significantly, and the band gap declined dramatically from 2.15 eV to 1.92 eV. Finally, the X-radiation response of a-Se was investigated as an important property, revealing there is a remarkable response speed of photogeneration current both X-ray on and X-ray off, with a requirement of only a very small electrical field.

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X ‐ r ay Photoconductivity and Typical Large‐Area X ‐ r ay Photoconductors

Kabir¹

2022

Photoconductivity and Photoconductive Materials

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Electron–hole pair creation energy in amorphous selenium for high energy photon excitation

Cited by 12 publications

References 17 publications

The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

Investigations on Structural, Optical and X-Radiation Responsive Properties of a-Se Thin Films Fabricated by Thermal Evaporation Method at Low Vacuum Degree

X ‐ r ay Photoconductivity and Typical Large‐Area X ‐ r ay Photoconductors

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