Photoinduced changes in amorphous selenium

2014 ◽  
Vol 92 (7/8) ◽  
pp. 663-666 ◽  
Author(s):  
F. Djefaflia ◽  
C. Mebarkia ◽  
A. Hafdallah ◽  
M.L. Benkhedir ◽  
A. Belfedal
Keyword(s):  
Thin Films ◽  
White Light ◽  
Room Temperature ◽  
Light Exposure ◽  
Red Light ◽  
Amorphous Selenium ◽  
Corning Glass ◽  
Visible Transmittance ◽  
Photoinduced Changes ◽  
Photoinduced Phenomena

Photoinduced phenomena in thin films of amorphous selenium (a-Se) have been a subject of intensive researches so far. Thin films of a-Se were deposited on corning glass by thermal evaporation, with several thicknesses. The influence of light exposure, with different colors (blue or red or natural white light), on the optical and structural properties of a-Se thin films was carried out by using ultraviolet–visible transmittance spectroscopy. It was found that the gap of the samples illuminated with blue and natural white light at room temperature shifts to lower energies. This photodarkening is stable at room temperature and is irreversible even after several days. On the other hand the photodarkening in the samples illuminated with red light is much smaller than that for samples illuminated with blue and natural white light. The photodarkening is accompanied by an increase in the refractive index. These results are discussed with results, previously obtained, about the photoinduced changes of the negative-U centers in, T– and T+, studied using time-of-flight (TOF) traces recorded on samples prepared in the same conditions. These TOF measurements show that the defect level T– at 0.4 eV above the valence band edge shifts to 0.5 eV under illumination with white light at room temperature. This effect is not seen if the illumination is done at 35 °C. These phenomena are attributed to nanocrystallization in the a-Se films.

Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

2003 ◽  
Vol 769 ◽  
Author(s):  
Asha Sharma ◽  
Deepak ◽  
Monica Katiyar ◽  
Satyendra Kumar ◽  
V. Chandrasekhar ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Weight ◽  
Light Source ◽  
Room Temperature ◽  
Light Exposure ◽  
Room Temperature Photoluminescence ◽  
Pl Spectrum ◽  
Pl Intensity ◽  
Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

The Growth of Transparent Conductive Al-Doped ZnO Thin Films at Room Temperature

2007 ◽  
Vol 124-126 ◽  
pp. 211-214
Author(s):  
Sang Moo Park ◽  
Takashi Tomemori ◽  
Tomoaki Ikegami ◽  
Kenji Ebihara
Keyword(s):  
Thin Films ◽  
Oxygen Pressure ◽  
Carrier Mobility ◽  
Room Temperature ◽  
Electrical And Optical Properties ◽  
Flexible Display ◽  
Glass Substrates ◽  
Visible Transmittance ◽  
Flexible Solar Cell ◽  
Doped Zno

High-quality transparent conductive Al-doped ZnO (AZO) thin films were deposited by pulsed laser deposition on quartz glass substrates at room temperature. We varied the growth condition in terms of oxygen pressure. The structure and electrical and optical properties of the as-grown AZO films were mainly investigated. The AZO films formed at room temperature showed a low electrical resistivity of 3.01×10-4 ) cm, a carrier concentration of 1.12×1021 cm-3 and a carrier mobility of 18.59 cm2/Vs at an oxygen pressure of 10 mTorr. A visible transmittance of above 83% was obtained. The present results suggest that optimized AZO films should be very useful and effective for flexible display, top emission type of OLEDs and for various other kinds of optoelectronic devices such as flexible solar cell or passive photo device.

scholarly journals PERTUMBUHAN PARUH ANAK ITIK MAGELANG (Anas javanica) AKIBAT INDUK YANG DISUPLEMENTASI KURKUMIN (Curcuma longa L.) DAN DIPAJAN CAHAYA MERAH

2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Luthfiana Ulil Albab ◽  
Sri Isdadiyanto ◽  
Muhammad Anwar Djaelani
Keyword(s):  
White Light ◽  
Egg Production ◽  
Light Exposure ◽  
Curcuma Longa ◽  
Red Light ◽  
Meat Production ◽  
Parametric Test ◽  
Wild Duck ◽  
Randomized Design ◽  
Length Width

ABSTRACTMagelang duck is the Indonesian wild duck that have high egg and meat production. To increase egg production hence in this research magelang ducks are supplemented with curcumin and exposure of white and red light.  The aim of the research to study growth beak duckling from parental magelang ducks that supplemented curcumin and red light exposure. The research design used  complete randomized design from fourdifferents group of ducks, i.e., A0B0 (duck without curcumin and white light exposure), A0B1 (duck without curcumin and red light exposure), A0B1 (curcumin dose of 18 mg/duck/day and white light exposure and A1B1 (curcumin dose 18 mg/duck/day and red light exposure). Five female ducklings were taken from each group and their morphometry were measured. The variables of this research were the length, width and height of beaks. The collected data were analized with Kruskal-Wallis non parametric test and would be further tested with Mann-Whitney-U test. The result of this research showed that curcumin supplementaion and red light exposure in ducks affected the magelang ducklings beak growth. Keywords : beaks, curcumin, growth, magelang ducks, red light. ABSTRAKItik magelang merupakan itik liar asli Indonesia yang memiliki produksi telur dan daging relatif tinggi. Untuk meningkatkan produksi telur maka pada penelitian ini itik magelang diberi suplementasi kurkumin serta pajanan cahaya putih dan merah. Penelitian ini bertujuan untuk mengkaji pengaruh pemberian kurkumin serta cahaya putih dan merah pada induk terhadap pertumbuhan paruh anak itik magelang. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap (RAL) yang berasal dari empat induk yang berbeda, yaitu induk A0B0 (tanpa diberi kurkumin dan dipapar cahaya putih),  A0B1 (tanpa diberi kurkumin dan  dipapar cahaya merah), A1B0 (dosis kurkumin 18 mg/ekor/hari dan paparan cahaya putih) dan A1B1 (dosis kurkumin 18 mg/ekor/hari pada cahaya merah). Masing-masing kelompok induk diambil lima ekor anak itik untuk diukur paruhnya. Variabel yang diamati berupa pengukuran panjang, lebar, dan tebal paruh. Data yang diperoleh dianalisis menggunakan uji non parametrik Kruskal-Wallis dan diuji lanjut menggunakan uji Mann-Whitney-U. Hasil penelitian ini menunjukkan bahwa suplementasi kurkumin dan pajanan cahaya putih serta merah pada induk secara umum dapat meningkatkan pertumbuhan paruh anak itik. Kata kunci: paruh, kurkumin, pertumbuhan, itik magelang, cahaya merah.

A next generation TCO Material for display systems: Molybdenum doped Indium oxide thin films

2006 ◽  
Vol 936 ◽  
Author(s):  
E. Elangovan ◽  
A Marques ◽  
R Martins ◽  
E Fortunato
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Time ◽  
Optical Band Gap ◽  
Optical Transmittance ◽  
Glass Substrates ◽  
Visible Transmittance ◽  
Sputtering Power ◽  
Spectra Properties ◽  
Display Systems

ABSTRACTThin films of indium molybdenum oxide (IMO) were rf sputtered onto glass substrates at room temperature. The films were studied as a function of sputtering power (ranging 40 – 180 W) and sputtering time (ranging 2.5 – 20 min). Thickness of the films found varied between 50 – 400 nm. The films were characterized for their structural (XRD), electrical (Hall measurements) and optical (Transmittance spectra) properties. XRD studies revealed that the films are amorphous for the sputtering power ≤ 100 W and deposition time ≤ 5 min. All the other films are polycrystalline and the strongest refection along (222) plane showing a preferential orientation. A minimum bulk resistivity of 2.65 × 10−3 Ω-cm and a maximum carrier concentration of 4.16 × 1020 cm−3 have been obtained for the films sputtered at 180 W (10 min). Whereas maximum mobility (19.5 cm2 V−1 s−1) has been obtained for the films sputtered at 80 W (10 min). A maximum visible transmittance of 90 % (500 nm) has been obtained for the films sputtered at 80 W (10 min) with a minimum of 27 % for those sputtered at 180 W. The optical band gap of the films found varying between 3.75 and 3.90 eV for various sputtering parameters.

scholarly journals Red Light Exposure Delays Appearance and Aroma Deterioration of Fresh-Cut Watermelon during Retail Display

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yue Shi ◽  
Yubin Wang ◽  
Yue Ma ◽  
Yong Xu ◽  
Xiaoyan Zhao ◽  
...  
Keyword(s):  
Weight Loss ◽  
White Light ◽  
Light Exposure ◽  
Red Light ◽  
Microbial Metabolism ◽  
Color Difference ◽  
The Self ◽  
Retail Display ◽  
Fresh Cut ◽  
Fruit Surface

Appearance and aroma deterioration are the main concerns during the retail display of fresh-cut watermelons. Here, fresh-cut watermelons were exposed to the red, green, blue, and conventional white light at 4°C for 4 days, respectively, and their resulting qualities were compared with the conventional white light as the control. Specifically, the red light presented its maximum emissions in 620–650 nm with a purity of 100% and an intensity of 1104.7 lux. The red light exposure reduced the weight loss to 1.81%, which was reduced by 51.1% of the control. The red light exposure reduced the color difference of the fruit surface significantly as well as maintaining its redness. The water-soaking ratio of the red light exposure was also reduced by 62.8% of the control. Moreover, the red light exposure delayed the aroma deterioration, which resulted from both microbial metabolism and the self-metabolism of volatiles of the fresh-cut watermelon. In summary, the red light exposure was better to delay the appearance and aroma deterioration of fresh-cut watermelons than the conventional white light during their retail display.

Light at Night and Measures of Alertness and Performance

2015 ◽  
Vol 18 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Mariana G. Figueiro ◽  
Levent Sahin ◽  
Brittany Wood ◽  
Barbara Plitnick
Keyword(s):  
White Light ◽  
Light Exposure ◽  
Red Light ◽  
Reaction Times ◽  
Light At Night ◽  
Improve Performance ◽  
Practical Applications ◽  
Circadian Phase ◽  
Dim Light ◽  
And Performance

Rotating-shift workers, particularly those working at night, are likely to experience sleepiness, decreased productivity, and impaired safety while on the job. Light at night has been shown to have acute alerting effects, reduce sleepiness, and improve performance. However, light at night can also suppress melatonin and induce circadian disruption, both of which have been linked to increased health risks. Previous studies have shown that long-wavelength (red) light exposure increases objective and subjective measures of alertness at night, without suppressing nocturnal melatonin. This study investigated whether exposure to red light at night would not only increase measures of alertness but also improve performance. It was hypothesized that exposure to both red (630 nm) and white (2,568 K) lights would improve performance but that only white light would significantly affect melatonin levels. Seventeen individuals participated in a 3-week, within-subjects, nighttime laboratory study. Compared to remaining in dim light, participants had significantly faster reaction times in the GO/NOGO test after exposure to both red light and white light. Compared to dim light exposure, power in the alpha and alpha-theta regions was significantly decreased after exposure to red light. Melatonin levels were significantly suppressed by white light only. Results show that not only can red light improve measures of alertness, but it can also improve certain types of performance at night without affecting melatonin levels. These findings could have significant practical applications for nurses; red light could help nurses working rotating shifts maintain nighttime alertness, without suppressing melatonin or changing their circadian phase.

Direct white-light emitting room-temperature-phosphorescence thin films with tunable two-color polarized emission through orientational hydrogen-bonding layer-by-layer assembly

2018 ◽  
Vol 6 (16) ◽  
pp. 4444-4449 ◽  
Author(s):  
Rui Gao ◽  
Xiaoyu Fang ◽  
Dongpeng Yan
Keyword(s):  
Thin Films ◽  
Hydrogen Bonding ◽  
White Light ◽  
Room Temperature ◽  
Bonding Layer ◽  
Layer By Layer ◽  
Room Temperature Phosphorescence ◽  
Light Emitting ◽  
Polarized Emission ◽  
Layer Assembly

Molecule-based room-temperature-phosphorescence (RTP) materials have received much attention recently.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

Investigation of ultra-thin films of YBa2Cu3O7−δ grown on MgO

1990 ◽  
Vol 48 (4) ◽  
pp. 6-7
Author(s):  
S.K. Streiffer ◽  
C.B. Eom ◽  
J.C. Bravman ◽  
T.H. Geballet
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
Multilayer Structures ◽  
Rf Power ◽  
Oxygen Loss ◽  
Transmission Electron ◽  
Single Target ◽  
Mtorr Argon

The study of very thin (<15 nm) YBa2Cu3O7−δ (YBCO) films is necessary both for investigating the nucleation and growth of films of this material and for achieving a better understanding of multilayer structures incorporating such thin YBCO regions. We have used transmission electron microscopy to examine ultra-thin films grown on MgO substrates by single-target, off-axis magnetron sputtering; details of the deposition process have been reported elsewhere. Briefly, polished MgO substrates were attached to a block placed at 90° to the sputtering target and heated to 650 °C. The sputtering was performed in 10 mtorr oxygen and 40 mtorr argon with an rf power of 125 watts. After deposition, the chamber was vented to 500 torr oxygen and allowed to cool to room temperature. Because of YBCO’s susceptibility to environmental degradation and oxygen loss, the technique of Xi, et al. was followed and a protective overlayer of amorphous YBCO was deposited on the just-grown films.

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