scholarly journals The effect of low dose γ-irradiation on the optoelectric properties of n-GaN based MSM structure

2021 ◽  
Author(s):  
Leyla Barghamadi ◽  
Shahab Norouzian Alam ◽  
Bijan Ghafari ◽  
Seyed Hassan Sedighy
Keyword(s):  
Dark Current ◽  
Low Dose ◽  
Prolonged Exposure ◽  
Localized States ◽  
Abnormal Behavior ◽  
Γ Irradiation ◽  
Space Applications ◽  
Γ Radiation ◽  
Metal Semiconductor Metal ◽  
Msm Structure

Abstract The room temperature effect of a low dose rate (10-4 rad (Si)/s) 60 Co γ-irradiation on the structural propertiesand dark current of the GaN-based metal-semiconductor-metal (MSM) structure has been studied. In contrast to previous studies, a non-monotonous dependence of the dark current with the γ-irradiation dose is observed. The intensity and linewidth of the photoluminescence (PL) peaks correlate with the changes in electrical characteristics and eventually degrade after prolonged exposure to the γ-radiation. The abnormal behavior of the MSM structure and particularly its I-V and PL characteristics are explained by considering the carrier transfer mechanism in the localized states. These phenomena are associated with the decrease of shallow donors’ density in localized states and the activation of the non-radiative centers as radiation dose increases. These experimental results and the mechanism presented are essential for understanding the interaction of the γ-irradiation with n-GaN and for estimation of reliability of GaN-based (opto)electronics in harsh conditions of γ-radiation (space applications, liquidation of consequences of technogenic catastrophes, etc.).

scholarly journals Механизмы частотно-зависимой проводимости мезопористого кремния при гамма-облучении малыми дозами

2019 ◽  
Vol 45 (11) ◽  
pp. 6
Author(s):  
В.В. Галушка ◽  
Э.А. Жаркова ◽  
Д.В. Терин ◽  
В.И. Сидоров ◽  
Е.И. Хасина
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Low Dose ◽  
Low Frequency ◽  
Lattice Vibrations ◽  
Γ Irradiation ◽  
Mesoporous Silicon ◽  
Γ Radiation ◽  
The Creation

Abstract — The effect of low-dose γ radiation on the mechanisms of low-frequency conductivity of mesoporous silicon has been studied. It has been shown that γ irradiation preserves the hopping character of conductivity at a change of the frequency of phonon lattice vibrations, a decrease in the size of the hop, and a shift of the level of the capture of traps to the Fermi level in the band gap, which makes the structure with mesoporous silicon irradiated by γ radiation promising for the creation of multifunctional resistive and capacitive devices.

Effects of initial concentration and irradiation dose to degradation of di butyl phthalate from phosphoric acid (30 % P2O5)

2018 ◽  
Vol 106 (11) ◽  
pp. 909-916
Author(s):  
Louisa Bounemia ◽  
Abdelhamid Mellah
Keyword(s):  
Organic Matter ◽  
Phosphoric Acid ◽  
Optimal Recovery ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Butyl Phthalate

Abstract The pretreatment of the phosphoric acid is a stage of utmost importance leading to an optimal recovery of the uranium present in this acid. To this end, the degradation of the organic matter which obstructs considerably this recovery was tested by γ irradiation. This study lies within the scope of the radiation/matter interaction; concerning the use of the γ irradiator as proceed of phosphoric acid purification by the degradation of di butyl phthalate (DBP). Studies of the interaction of γ radiation with phosphoric acid solutions polluted by an organic matter concern the study of the influence of some parameters such as: dose rate (0.5–35 kGy), initial concentration (50–500 mg/L) of the pollutant, pH and % in P2O5 on the degradation of organic matter by γ irradiation. The reactions followed pseudo first order kinetics for different initial concentrations. The results made it possible to say that the degradation of di butyl phthalate by γ irradiation is dependent on the amount of the concentration of DBP and pH. The G-values decreased with absorbed doses, and increased with higher initial concentrations.Purification of phosphoric acid by γ radiation does not degrade the quality of this acid.

scholarly journals Suppression of dark current in GeO_x-passivated germanium metal-semiconductor-metal photodetector by plasma post-oxidation

2015 ◽  
Vol 23 (13) ◽  
pp. 16967 ◽  
Author(s):  
Jian Kang ◽  
Rui Zhang ◽  
Mitsuru Takenaka ◽  
Shinichi Takagi
Keyword(s):  
Dark Current ◽  
Metal Semiconductor Metal

scholarly journals Phosphoprotein profiles of candidate markers for early cellular responses to low-dose γ-radiation in normal human fibroblast cells

2017 ◽  
Vol 58 (3) ◽  
pp. 329-340 ◽  
Author(s):  
Ji-Hye Yim ◽  
Jung Mi Yun ◽  
Ji Young Kim ◽  
In Kyung Lee ◽  
Seon Young Nam ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Human Fibroblast ◽  
Low Dose ◽  
High Dose ◽  
Normal Human Fibroblast ◽  
Low Dose Radiation ◽  
Γ Radiation ◽  
Normal Human ◽  
Dose Radiation ◽  
In Cells

Abstract Ionizing radiation causes biological damage that leads to severe health effects. However, the effects and subsequent health implications caused by exposure to low-dose radiation are unclear. The objective of this study was to determine phosphoprotein profiles in normal human fibroblast cell lines in response to low-dose and high-dose γ-radiation. We examined the cellular response in MRC-5 cells 0.5 h after exposure to 0.05 or 2 Gy. Using 1318 antibodies by antibody array, we observed ≥1.3-fold increases in a number of identified phosphoproteins in cells subjected to low-dose (0.05 Gy) and high-dose (2 Gy) radiation, suggesting that both radiation levels stimulate distinct signaling pathways. Low-dose radiation induced nucleic acid–binding transcription factor activity, developmental processes, and multicellular organismal processes. By contrast, high-dose radiation stimulated apoptotic processes, cell adhesion and regulation, and cellular organization and biogenesis. We found that phospho-BTK (Tyr550) and phospho-Gab2 (Tyr643) protein levels at 0.5 h after treatment were higher in cells subjected to low-dose radiation than in cells treated with high-dose radiation. We also determined that the phosphorylation of BTK and Gab2 in response to ionizing radiation was regulated in a dose-dependent manner in MRC-5 and NHDF cells. Our study provides new insights into the biological responses to low-dose γ-radiation and identifies potential candidate markers for monitoring exposure to low-dose ionizing radiation.

Effect of γ irradiation on the parameters of localized states in p-InSe and n-InSe⟨Sn⟩ single crystals

2010 ◽  
Vol 36 (7) ◽  
pp. 642-644 ◽  
Author(s):  
S. N. Mustafaeva ◽  
A. A. Ismaĭlov ◽  
M. M. Asadov
Keyword(s):  
Single Crystals ◽  
Localized States ◽  
Γ Irradiation

Efficient monitoring of dosimetric behaviour for copper nanoparticles through studying its optical properties

2019 ◽  
Vol 107 (6) ◽  
pp. 523-529 ◽  
Author(s):  
Mohamad Bekhit ◽  
Asmaa Sobhy ◽  
Zakaria I. Ali ◽  
Sameh M. Gafar
Keyword(s):  
Copper Nanoparticles ◽  
Metal Ion ◽  
Copper Ions ◽  
Dose Range ◽  
Ion Concentration ◽  
Nanocomposite Films ◽  
Poly Vinyl Alcohol ◽  
High Dose ◽  
Γ Irradiation ◽  
Γ Radiation

Abstract A novel high-dose dosimeter based on γ radiation reduction of copper ions and formation of copper metal inside polymer matrix were investigated. γ radiation induced synthesis of copper nanoparticles (CuNPs) in poly vinyl alcohol films were studied by UV-Visible Spectrophotometer, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The optical absorption spectra showed that the Cu/PVA nanocomposite films have surface plasmon resonance (SPR) of copper nanoparticles which depending on irradiation doses. Upon γ irradiation these films turns its color from faint blue to deep reddish brown depending on metal ion concentration. The XRD pattern and FTIR spectrum confirm the formation of the CuNPs. The response of Cu/PVA nanocomposite dosimeters depends on both the irradiation doses and concentration of copper precursor. The dose range for these films was from 50 to 650 kGy, revealing its important applications for high dose dosimetry. Cu/PVA nanocomposites films exhibit good post-irradiation stability in dark and light.

Sign in / Sign up

Export Citation Format

Share Document