Ni2Si/4H-SiC Schottky Photodiodes for Ultraviolet Light Detection

2016 ◽  
Vol 858 ◽  
pp. 1015-1018
Author(s):  
Massimo Mazzillo ◽  
Antonella Sciuto ◽  
Fabrizio Roccaforte ◽  
Corrado Bongiorno ◽  
Roberto Modica ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ultraviolet Light ◽  
Uv Radiation ◽  
Radiation Monitoring ◽  
Uv Exposure ◽  
Light Detection ◽  
Uv Detectors ◽  
Suitable Material ◽  
Exposure Risks ◽  
Schottky Photodiode

Ultraviolet (UV) monitoring is of great interest in the healthcare field to prevent excessive UV exposure risks. In the last years silicon carbide (SiC) has emerged as a suitable material for the fabrication of UV detectors. In this paper we propose a 4H-SiC Schottky photodiode with a continuous very thin Ni2Si layer operating at 0V, properly designed for UV radiation monitoring.

MgxZn1-xO-Based Schottky Photodiode for Highly Color-Selective Ultraviolet Light Detection

2008 ◽  
Vol 1 ◽  
pp. 121201 ◽  
Author(s):  
Masaki Nakano ◽  
Takayuki Makino ◽  
Atsushi Tsukazaki ◽  
Kazunori Ueno ◽  
Akira Ohtomo ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Detection ◽  
Schottky Photodiode

UV Irradiation of Shell Eggs: Effect on Populations of Aerobes, Molds, and Inoculated Salmonella typhimurium

1997 ◽  
Vol 60 (6) ◽  
pp. 639-643 ◽  
Author(s):  
FUENG-LIN KUO ◽  
JOHN B. CAREY ◽  
STEVEN C. RICKE
Keyword(s):  
Salmonella Typhimurium ◽  
Uv Radiation ◽  
Uv Light ◽  
The Other ◽  
Uv Exposure ◽  
Microbial Populations ◽  
Aerobic Bacteria ◽  
Fluorescent Light ◽  
Uv Treatment ◽  
Shell Eggs

The effects were investigated of 254-nm UV radiation on populations of Salmonella typhimurium, aerobes, and molds on the shells of eggs. In the first experiment, the CFU of attached S. typhimurium cells on unwashed clean shell eggs were determined after 0, 1, 3, 5, and 7 min of UV treatment (620 μW/cm2) on both ends of the egg. All UV treatments significantly reduced S. typhimurium CFU (P < .01). UVtreatment (620 μW/cm2) in 1-min alternating light and dark cycles for 5 min (three light and two dark) was compared to 0, 3, and 5 min of UV treatment. No significant differences in microbial populations were observed among light and dark cycles and the other UV treatments. In a subsequent experiment, the same UV treatments were utilized to evaluate photoreactivation. After UV exposure, eggs were exposed to 1 h of fluorescent light or I h of darkness or cultured immediately. S. typhimurium CFU were significantly (P < .01) reduced by the UV treatments. However, no significant differences between microbial populations exposed to UV treatment and UV radiation plus photoreactivation were detected. For studies of aerobic bacteria and molds, different UV treatment times (0, 15, and 30 min) at the intensity of 620 μW/cm2 and different intensities (620, 1350, and 1720 μW/cm2) for 15 min were evaluated. Mold CFU per egg were either 0 or 1 for all UV treatments and a 99% reduction of CFU of aerobic bacteria per egg were observed for all UV treatments. It appears from these studies that UV light can significantly reduce populations of S. typhimurium, aerobes, and molds on shell eggs.

scholarly journals The Early Days of Personal Solar Ultraviolet Dosimetry

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 125 ◽  
Author(s):  
Brian Diffey
Keyword(s):  
Uv Radiation ◽  
Human Exposure ◽  
Ground Level ◽  
Uv Exposure ◽  
Population Exposure ◽  
Atmospheric Ozone ◽  
Quantitative Understanding ◽  
Solar Uv ◽  
The Impact ◽  
Solar Ultraviolet

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.

Evaluation of the Effect of Ultraviolet Light Excitation during Characterization of Silicon Carbide Epitaxial Layers

2018 ◽  
Vol 924 ◽  
pp. 261-264
Author(s):  
Hrishikesh Das ◽  
Swapna Sunkari ◽  
Oener Akdik ◽  
Andrei Konstantinov ◽  
Krister Gumaelius ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ultraviolet Light ◽  
Defect Detection ◽  
Uv Light ◽  
Surface Treatments ◽  
Uv Laser ◽  
Original State ◽  
Optimal Surface ◽  
Light Excitation

The scanning of Silicon Carbide (SiC) epitaxy wafers for defects by ultraviolet (UV) laser or lamps is widely prevalent. In this work, we document the effects of UV light excitation on the SiC epitaxy material. An increase in background photoluminescence (PL) is observed after repeated scans. The effect of this increase on defect detection is shown. Optimal surface treatments to recover the material back to the original state are demonstrated. Further, some surface treatments are proposed which reduce the effect of the UV light excitation and prevent to a large extent the rise in background PL.

scholarly journals Effects of Ultraviolet Radiation on Recycled and Virgin HDPE Corrugated Pipes Used in Road Drainage Systems

2021 ◽  
Author(s):  
Khanh Q. Nguyen ◽  
Patrice Cousin ◽  
Khaled Mohamed ◽  
Mathieu Robert ◽  
Adel El-Safty ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Uv Light ◽  
Morphological Structure ◽  
Tensile Tests ◽  
Repair Process ◽  
Thermomechanical Properties ◽  
Uv Exposure ◽  
Scanning Calorimetry ◽  
Drainage Systems ◽  
Significant Difference

Abstract High-density polyethylene (HDPE) pipe is one of the materials of interest for use in road drainage systems. The combination of ultraviolet (UV) light, temperature, and moisture can produce weak spots and lead to pipe degradation during the storage, installation, and repair process. The objective of this study was to evaluate changes in the chemical, morphological structure, and thermomechanical properties of recycled and virgin pipes under UV exposure. Laboratory accelerated aging tests were conducted by exposing pipes to UV for 3600 hours with an irradiance of 0.89 W/(m2 nm) at a wavelength of 340 nm. A cycle of 12 hours—comprised of 8 hours of UV radiation at 60°C and 4 hours of no UV radiation at 50°C corresponding to no water condensation—was performed to condition the specimens. HDPE specimens were taken out after 3600 hours and analyzed with FTIR (Fourier-transform infrared spectroscopy), SEM (scanning electron microscopy), DSC (differential scanning calorimetry), oxidative-induction time (OIT) measurements, and tensile tests. The results show that the recycled pipes maintained good properties and were not significantly affected by UV radiation, similarly to the virgin pipes. Statistical analysis using one-way analysis of variance (ANOVA) shows that there was no significant difference between tensile strength, elastic modulus, and hardness measurements before and after UV exposure. There were only a few small changes in the surface of the pipes. The addition of carbon black, antioxidants, and UV stabilizers prevented further aging of the pipes during UV exposure.

Selective 4H-SiC UV Detectors

2013 ◽  
Vol 740-742 ◽  
pp. 1014-1017
Author(s):  
Evgenia V. Kalinina ◽  
O. Konstantinov ◽  
A.A. Lebedev ◽  
Yu. Gol’dberg
Keyword(s):  
Quantum Efficiency ◽  
Uv Radiation ◽  
Wavelength Range ◽  
Optical Transition ◽  
Human Beings ◽  
Radiation Level ◽  
Uv Detectors ◽  
Uv Photodetectors ◽  
Oncological Diseases ◽  
Direct Optical Transition

Carcinogenic (bactericidal) radiation (λ = 200–300 nm with a peak at 254 nm) is present in natural (Sun) and artificial (lamps) source of UV radiation. Its intensity is very low as compared to other types of radiation, but it strongly affects the health of human beings. To prevent oncological diseases, it is important to monitor the carcinogenic radiation level; i.e., selective photodetectors are required. A UV photodetectors based on n-4H-SiC Schottly barriers and p+-n junctions are proposed. The quantum efficiency spectrum of such detectors is very close to the spectrum of relative action of carcinogenic radiation on human beings due to the direct optical transition at 4.9 eV in 4H-SiC. The quantum efficiency (at the spectral peak 254 nm) amounts to about 0.3 electrons/photon for virtually zero sensitivity in other spectral regions. Quantum efficiency in the wavelength range 247–254 nm is practically independent of temperature in the range from −100 to +300°C.

A surface acoustic wave impedance-loaded high sensitivity sensor with wide dynamic range for ultraviolet light detection

2019 ◽  
Vol 296 ◽  
pp. 70-78 ◽  
Author(s):  
G. Ya. Karapetyan ◽  
V.E. Kaydashev ◽  
D.A. Zhilin ◽  
M.E. Kutepov ◽  
T.A. Minasyan ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Ultraviolet Light ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Wave Impedance ◽  
Wide Dynamic Range ◽  
Light Detection

A novel multifunction photochromic metal–organic framework for rapid ultraviolet light detection, amine-selective sensing and inkless and erasable prints

2019 ◽  
Vol 6 (11) ◽  
pp. 3077-3082 ◽  
Author(s):  
Li Li ◽  
Zu-Ming Tu ◽  
Yang Hua ◽  
Xiao-Nan Li ◽  
Hai-Yu Wang ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Metal Organic Framework ◽  
Light Detection ◽  
Low Intensity ◽  
Metal Organic ◽  
Organic Framework

The system shows efficient and fast low intensity ultraviolet light detection, amine-selective sensing and also be used as inkless and erasable print.

scholarly journals Platelet-activating Factor, a Molecular Sensor for Cellular Damage, Activates Systemic Immune Suppression

2002 ◽  
Vol 195 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Jeffrey P. Walterscheid ◽  
Stephen E. Ullrich ◽  
Dat X. Nghiem
Keyword(s):  
Skin Cancer ◽  
Uv Radiation ◽  
Immune Suppression ◽  
Critical Role ◽  
Platelet Activating Factor ◽  
Cellular Damage ◽  
Uv Exposure ◽  
Delayed Type Hypersensitivity ◽  
Lipid Mediator ◽  
Paf Receptor

Ultraviolet (UV) radiation plays a critical role in the induction of nonmelanoma skin cancer. UV radiation is also immune suppressive, and the immune suppression induced by UV irradiation has been identified as a major risk factor for skin cancer induction. Previously, we showed that UV exposure activates a cytokine cascade involving prostaglandin (PG)E2, interleukin (IL)-4, and IL-10 that induces immune suppression. However, the earliest molecular events that occur immediately after UV exposure, especially those upstream of PGE2, are not well defined. UV-irradiated keratinocytes secrete the inflammatory phospholipid mediator, platelet-activating factor (PAF). Because PAF upregulates the production of immunomodulatory compounds, including PGE2, we tested the hypothesis that UV-induced PAF activates cytokine production and initiates UV-induced immune suppression. Both UV and PAF activated cyclooxygenase (COX)-2 and IL-10 reporter gene construct transcription. PAF mimicked the effects of UV in vivo and suppressed delayed-type hypersensitivity (DTH). Furthermore, immune suppression was blocked when UV-irradiated mice were injected with PAF receptor antagonists. In addition to the well-known role of PAF as a proinflammatory lipid mediator, we propose that the PAF receptor senses cellular damage through the recognition of PAF and/or PAF-like molecules, such as oxidized phosphatidylcholine, which activates cytokine transcription and induces systemic immune suppression.

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