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Journal ArticleDOI

Gamma Radiation Detection Response of Pt/PZT/SRO Based Capacitor for Dosimetry Application

01 Oct 2020-IEEE Electron Device Letters (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 41, Iss: 10, pp 1564-1567
TL;DR: In this paper, the effect of gamma radiation on the intrinsic electrical behavior of PZT capacitors was explored in form of the currentvoltage and capacitance-voltage properties.
Abstract: Radiation induced changes in the electrical properties of PbZrTiO3 (PZT) thin films have been studied for dosimetry application. The radiation detection was based on radiation induced changes in the electrical properties under the influence of gamma radiation. Epitaxial heterostructure of ferroelectric PbZr0.52 Ti0.48O3 (001)/SrRuO3 (SRO) were grown on single crystal SrTiO3 (001) substrates by pulsed laser deposition and platinum (Pt) electrode was deposited on top of the PZT film. The maximum capacitance of the heteroepitaxial capacitor devices was $\approx ~25$ pF with a corresponding small leakage current. The effect of gamma ( $\gamma $ -ray) irradiation on the intrinsic electrical behavior of the Lead Zirconate Titanate (PZT) capacitor devices were explored in form of the current–voltage (I–V) and capacitance–voltage (C–V) properties. The PZT devices were exposed to a 60Co Gamma source with 2.8 kGy/h dose rate from 0 kGy to 400 kGy doses. Gamma radiation induced broadening was observed in full width half maxima (FWHM) of the x-ray diffraction (00l) peak with the increasing gamma doses. All devices showed a consistence changes in conductance and capacitance with increasing gamma doses. The results demonstrated linear relationship in electrical response of PZT thin-film capacitors as a function of gamma doses. The device showed significant changes in the values of current and capacitance with the increase in dose up to 400 kGy and are therefore suitable for high-dose dosimetry applications.
Citations
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Journal ArticleDOI
01 May 1957-Nature
TL;DR: In this article, Bethe and Morrison present a theory of elementary nuclear theory, which they call the "elementary nuclear theory" (ENTT), based on the concept of the atom.
Abstract: Elementary Nuclear Theory By Prof. Hans A. Bethe and Prof. Philip Morrison. Second edition. Pp. xi + 274. (New York: John Wiley and Sons, Inc.; London: Chapman and Hall, Ltd., 1956.) 50s. net.

308 citations

References
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Journal ArticleDOI
01 May 1957-Nature
TL;DR: In this article, Bethe and Morrison present a theory of elementary nuclear theory, which they call the "elementary nuclear theory" (ENTT), based on the concept of the atom.
Abstract: Elementary Nuclear Theory By Prof. Hans A. Bethe and Prof. Philip Morrison. Second edition. Pp. xi + 274. (New York: John Wiley and Sons, Inc.; London: Chapman and Hall, Ltd., 1956.) 50s. net.

308 citations

Journal ArticleDOI
23 Mar 2000-Nature
TL;DR: Far-infrared ellipsometry and low-frequency dielectric measurements in SrTiO3 thin films demonstrate that the Lyddane–Sachs–Teller relation between the optical-phonon eigenfrequencies and the dielectic constant is fully maintained, as is the case in the bulk material.
Abstract: Understanding the behaviour of the dielectric constant in ferroelectric thin films remains a challenging problem. These ferroelectric materials have high static dielectric constants, and so are important for their applications in high-storage-density capacitor structures such as dynamic random access memory (DRAM). But the dielectric constant tends to be significantly reduced in thin films, thereby limiting the potential benefit of ferroelectrics for memory devices. Extensive studies have shown that this phenomenon could be caused by a 'dead layer' of very low dielectric constant between the ferroeletric film and the electrode. And, although very few direct measurements are in fact available, it has been recognized that the lattice dynamical properties in the thin films should also play a key role in the reduction of the dielectric constant. Here we report far-infrared ellipsometry and low-frequency dielectric measurements in SrTiO3 thin films, which demonstrate that the Lyddane-Sachs-Teller relation between the optical-phonon eigenfrequencies and the dielectric constant is fully maintained, as is the case in the bulk material. This indicates that the dramatic reduction of the dielectric constant is a consequence of a profound change of the lattice dynamical properties, in particular of the reduced softening of its lowest optical-phonon mode. Our results therefore provide a better understanding of the fundamental limitations of the dielectric constant values in ferroelectric thin films.

243 citations


"Gamma Radiation Detection Response ..." refers background in this paper

  • ...vacancy defects along with stress in the film, have shown important role on the capacitance behaviour of PZT film [27]....

    [...]

Journal ArticleDOI
TL;DR: The proposed degradation mechanisms reported in the literature are thoroughly reviewed and the microscopic mechanisms and their implications for solar cells are discussed.
Abstract: Organic-inorganic perovskites are well suited for optoelectronic applications. In particular, perovskite single and perovskite tandem solar cells with silicon are close to their market entry. Despite their swift rise in efficiency to more than 21%, solar cell lifetimes are way below the needed 25 years. In fact, comparison of the time when the device performance has degraded to 80% of its initial value (T80 lifetime) of numerous solar cells throughout the literature reveals a strongly reduced stability under illumination. Herein, the various detrimental effects are discussed. Most notably, moisture- and heat-related degradation can be mitigated easily by now. Recently, however, several photoinduced degradation mechanisms have been observed. Under illumination, mixed perovskites tend to phase segregate, while, further, oxygen catalyzes deprotonation of the organic cations. Additionally, during illumination photogenerated charge can be trapped in the NH antibonding orbitals causing dissociation of the organic cation. On the other hand, organic-inorganic perovskites exhibit a high radiation hardness that is superior to crystalline silicon. Here, the proposed degradation mechanisms reported in the literature are thoroughly reviewed and the microscopic mechanisms and their implications for solar cells are discussed.

150 citations

Journal ArticleDOI
TL;DR: In this article, the electronic structure of oxygen vacancies in perovskite oxides was studied using the Heyd, Scuseria, Ernzerhof (HSE) hybrid density functional.
Abstract: The electronic structure of oxygen vacancies in bulk perovskite oxides SrTiO${}_{3}$ and LaAlO${}_{3}$ is studied using the Heyd, Scuseria, Ernzerhof (HSE) hybrid density functional. In SrTiO${}_{3}$ the oxygen vacancy defect introduces a localized state comprised of $3{d}_{{z}^{2}}$ and $4{p}_{z}$ orbitals of the adjacent Ti atoms. This results in a bound state 0.7 eV below the conduction band edge. For LaAlO${}_{3}$, the oxygen vacancy creates a deep state 2.19 eV below the conduction band edge. The defect state is a hybrid of the adjacent La 5$d$ and the Al 3$p$ states. We compute the formation energies of the neutral oxygen vacancy defect V${}^{0}$ in bulk SrTiO${}_{3}$ and LaAlO${}_{3}$ to be 6.0 and 8.3 eV, respectively.

132 citations


Additional excerpts

  • ...stable defect in perovskite oxides [33]....

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Journal ArticleDOI
TL;DR: Stability study of perovskite solar cells under gamma-rays and visible light simultaneously is reported, and defect density characterization reveals that gamma-ray irradiation does not induce electronic trap states.
Abstract: Organohalide metal perovskites have emerged as promising semiconductor materials for use as space solar cells and radiation detectors. However, there is a lack of study of their stability under operational conditions. Here a stability study of perovskite solar cells under gamma-rays and visible light simultaneously is reported. The perovskite active layers are shown to retain 96.8% of their initial power conversion efficiency under continuous irradiation of gamma-rays and light for 1535 h, where gamma-rays have an accumulated dose of 2.3 Mrad. In striking contrast, a glass substrate shows obvious loss of transmittance under the same irradiation conditions. The excellent stability of the perovskite solar cells benefits from the self-healing behavior to recover its efficiency loss from the early degradation induced by gamma-ray irradiation. Defect density characterization reveals that gamma-ray irradiation does not induce electronic trap states. These observations demonstrate the prospects of perovskite materials in applications of radiation detectors and space solar cells.

83 citations


"Gamma Radiation Detection Response ..." refers background in this paper

  • ...Yang et al [18] have reported the resistance of perovskite solar cells against γ -ray irradiation with higher total exposure dose....

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  • ...Yang et al [18] have reported the resistance of perovskite solar cells against γ -ray irradiation with higher...

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