The Relationship Between Surface Chemistry and Photoluminescence of Porous Silicon

1993 ◽  
Vol 298 ◽  
Author(s):  
Kun-Hsi Li ◽  
Chaochieh Tsai ◽  
Joe C. Campbell ◽  
Milan Kovar ◽  
John M White
Keyword(s):  
Surface Chemistry ◽  
Marked Decrease ◽  
Blue Shift ◽  
Surface Species ◽  
Silicon Hydride ◽  
Porous Si ◽  
Luminescence Process ◽  
The Relationship ◽  
Green Photoluminescence ◽  
Si Wafer

AbstractGreen photoluminescence (PL) is observed from an as-anodized porous Si wafer immersed in the anodization electrolyte and the PL turns red after the sample is removed from the electrolyte and is blown dry. The PL of porous Si immersed in alcohol exhibits a blue shift and a marked decrease in intensity relatively to dry, as-anodized wafers. However, when the immersed samples are treated with UV for a few minutes, the PL peak shifts to a longer wavelength. Fourier-transform infrared spectroscopy reveals that alkoxy surface species and silicon hydride species backbonded to oxygen atoms appear on the UV-treated samples. Furthermore, the PL characteristics and surface species of the UV-treated samples can be recovered to those of as-anodized wafers by dipping in HF. These results point out the importance of surface chemistry in the luminescence process of porous Si.

Blue and Green Electroluminescence from Porous Materials

1994 ◽  
Vol 358 ◽  
Author(s):  
H. Mimura ◽  
T. Matsumoto ◽  
Y. Kanemitsu
Keyword(s):  
Porous Materials ◽  
Blue Light ◽  
Porous Si ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Uv Illumination ◽  
Display Technology ◽  
Porous Sic ◽  
The Relationship ◽  
Green Photoluminescence

ABSTRACTIn applying porous Si (PS) to color display technology, it is important to fabricate light emitting devices with three primary colors. However, there have been few reports on blue and green electroluminescence (EL), and its mechanism (even the relationship between PL and EL spectra) is unclear. To obtain blue and green EL and to investigate its mechanism, we have formed PS anodized under UV illumination (UV-PS) with green photoluminescence (PL) and porous SiC with blue PL. Consequently, green and blue light emitting devices were successfully fabricated by using these materials. The observed spectra are from 350 to 750 nm with a peak of, 520 nm for ITO / UV-PS junctions and from 300 to 600 nm with a peak of 470 nm for ITO / porous SiC junctions. The EL mechanism is also discussed by reference to experimental results of comparing PL and EL spectra and of investigating the dependence of EL intensity on current.

Effects of hemorrhage and hepatic nerve stimulation on venous compliance and unstressed volume in cat liver

1987 ◽  
Vol 65 (11) ◽  
pp. 2168-2174 ◽  
Author(s):  
C. V. Greenway
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Nerve Stimulation ◽  
Marked Decrease ◽  
Venous Compliance ◽  
Remarkable Feature ◽  
Unstressed Volume ◽  
Passive Response ◽  
The Relationship ◽  
Blood Volumes

Intrahepatic blood volume–pressure relationships were studied using plethysmography to measure hepatic blood volume and a hepatic venous long-circuit to control intrahepatic pressure. In cats anesthetized with pentobarbital or with ketamine–chloralose, hemorrhage (to reduce hepatic blood flow to 60% of control) caused marked reductions in hepatic blood volume and intrahepatic pressure but did not significantly change hepatic blood volume–pressure relationships. We were unable to demonstrate an active reflex venous response to hemorrhage in these preparations, although a large passive response occurred. The volume–pressure relationships in innervated livers were different from those in denervated livers: apparent venous compliance was much greater and apparent unstressed volume was zero or negative. Hepatic nerve stimulation in denervated livers caused a marked decrease in hepatic blood volume at low intrahepatic pressures but failed to alter hepatic blood volumes at high intrahepatic pressures (15 mmHg) (1 mmHg = 133.3 Pa). This resulted in large apparent compliances and apparently negative unstressed volumes, as seen in the innervated livers. Thus blood volume–pressure relationships in innervated livers may not give valid measurements of compliance and unstressed volume. A remarkable feature in all these experiments was the linearity of the relationship between hepatic blood volume and intrahepatic pressure. Exudation of fluid begins at higher intrahepatic pressures in innervated compared with denervated livers.

Si2p Core Level Absorption and Photoemission Spectra of Porous Si

1992 ◽  
Vol 283 ◽  
Author(s):  
Hisao Nakashima ◽  
Koichi Inoue ◽  
Kenzo Maehashi
Keyword(s):  
Synchrotron Radiation ◽  
Electronic Structures ◽  
Energy Shift ◽  
Blue Shift ◽  
Photo Luminescence ◽  
High Energy ◽  
Core Level ◽  
Oxidation States ◽  
Porous Si ◽  
The Core

ABSTRACTSi2p core level absorption and photoemission spectra are taken for different porous Si layers using synchrotron radiation, toknow the electronic structures of porous Si. The core level absorption spectra show the high energy shift of the conduction band which correlates with the photo-luminescence blue shift. The oxidation states of porous Si are clarified from the photoemission spectra.

Patterning of proteins into nanostripes on Si-wafer over large areas: a combination of Langmuir–Blodgett patterning and orthogonal surface chemistry

Soft Matter ◽  
2011 ◽  
Vol 7 (3) ◽  
pp. 861-863 ◽  
Author(s):  
Yong Li ◽  
Julia C. Niehaus ◽  
Yueyue Chen ◽  
Harald Fuchs ◽  
Armido Studer ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Langmuir Blodgett ◽  
Orthogonal Surface ◽  
Si Wafer

Novel Miniature DMFC With Monolithic Si Electrodes

2009 ◽  
Author(s):  
Masanori Hayase ◽  
Yosuke Saito
Keyword(s):  
Metal Layer ◽  
Catalyst Layer ◽  
Pt Catalyst ◽  
Galvanic Replacement ◽  
Porous Si ◽  
Si Substrate ◽  
Catalyst Layers ◽  
Novel Structure ◽  
Si Wafer ◽  
Immersion Plating

A through-chip porous Ru-Pt catalyst layer was fabricated on a Si wafer and a novel miniature DMFC (Direct Methanol Fuel Cell) was realized. Recently, we found that porous noble metal layer can be synthesized on Si substrate by immersion plating on a porous Si. In order to realize a DMFC with our novel structure, a porous Ru layer was synthesized on the Si substrate using the immersion plating on the porous Si, then Pt was deposited by galvanic replacement reaction on the porous Ru. The porous Ru-Pt structure showed catalytic activity on methanol oxidization. A through-chip porous Ru-Pt layer was fabricated on a Si wafer by plasma etching and monolithic electrodes with catalyst layers and fuel channels were realized. A preliminary DMFC prototype successfully demonstrated power generation of 2mW/cm2.

Photoluminescence (PL) and Optically Detected Magnetic Resonance (ODMR) Study of Visible Light Emission from Porous Si

1991 ◽  
Vol 256 ◽  
Author(s):  
P. A. Lane ◽  
L. S. Swanson ◽  
J. Shinar ◽  
S. Chumbley
Keyword(s):  
Light Emission ◽  
Porous Si ◽  
Temperature Dependent ◽  
X Band ◽  
Amorphous Si ◽  
Optically Detected ◽  
Increasing Temperature ◽  
Hydrogenated Amorphous ◽  
Visible Light Emission ◽  
Si Wafer

ABSTRACTThe photoluminescence (PL) and X-band ODMR of porous Si layers is described and discussed. The layers were prepared by anodizing the (100) face of a Si wafer at 20 mA/cm2 in 20% HF for 5 mai and passively soaking them in 36% HF for up to 10 hrs. The PL was broad and featureless, extending from ˜1.5 to ˜2.1 eV and peaking at 1.68 eV. Its intensity slightly increased upon cooling to 90 K, and then strongly decreased at lower temperatures. A ˜20 G wide asymmetric PL-enhancing ODMR was observed at g ˜2.0031 ±I 0.0009, which could be fit to a sum of two Gaussians. Their g-values were slightly temperature dependent. The ODMR intensity strongly decreased with increasing temperature, and was unobservable above ˜80 K. The results are compared to the optical properties of hydrogenated amorphous Si.

Electronic Structures of Oligomers of Pyrrole

2010 ◽  
Vol 663-665 ◽  
pp. 658-661 ◽  
Author(s):  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Electronic Structures ◽  
Energy Gap ◽  
Tight Binding ◽  
One Dimensional ◽  
Extended Hückel ◽  
The Relationship ◽  
Green Photoluminescence

The electronic structures of oligomers of pyrrole have been calculated using the extended Hückel tight-binding program. The energy diagrams are shown for oligomers as the number of the repeating unit in the oligomers increases from 1 to 16. The relationship between the energy gap of the oligomers and the number of the repeating unit in the oligomers is established. Blue-green photoluminescence and electroluminescence from one-dimensional polypyrrole are predicted.

scholarly journals Tolerance to tumor necrosis factor in rats and the relationship to endotoxin tolerance and toxicity.

1988 ◽  
Vol 168 (1) ◽  
pp. 95-105 ◽  
Author(s):  
D L Fraker ◽  
M C Stovroff ◽  
M J Merino ◽  
J A Norton
Keyword(s):  
Tumor Necrosis ◽  
Marked Decrease ◽  
Lethal Dose ◽  
Endotoxin Tolerance ◽  
Humoral Immune ◽  
Histopathologic Changes ◽  
Induced Tolerance ◽  
The Relationship ◽  
Necrosis Factor ◽  
Tolerant State

Treatment of rats with recombinant human TNF initially causes a marked decrease in food intake, a loss of body weight, and a negative nitrogen balance. These alterations normalize with continued twice daily intraperitoneal injections of the same dose. Rats tolerized to TNF in this manner are refractory to a lethal dose of TNF. Also, TNF-pretreated and -tolerized rats have prolonged survival and reversed histopathologic changes after injection of a lethal dose of endotoxin compared with control animals. The TNF-tolerant state is dependent on the dose of TNF used and the length of TNF pretreatment. TNF-induced tolerance is relatively short lived, being present 2-4 d after TNF pretreatment and dissipating by 2 wk. Rats made tolerant to endotoxin are also tolerant to a lethal dose of TNF. A bidirectional crossreacting tolerance exists between TNF and endotoxin. The mechanism of TNF tolerance is unclear, but it does not appear to be due to a humoral immune response or a perturbation of the uptake and clearance of injected TNF.

scholarly journals RUNT DISEASE INDUCED IN NEONATAL MICE BY STERILE BACTERIAL VACCINES

1964 ◽  
Vol 120 (5) ◽  
pp. 795-804 ◽  
Author(s):  
Richard D. Ekstedt ◽  
Edwin T. Nishimura
Keyword(s):  
Marked Decrease ◽  
Lymphoid Tissues ◽  
Repeated Injection ◽  
Wasting Disease ◽  
Adrenal Hormones ◽  
Icr Mice ◽  
Homologous Antiserum ◽  
Severity Of The Disease ◽  
Relationship Of ◽  
The Relationship

A form of runt disease has been produced in neonatal CF-1 and ICR mice by the repeated injection of 109 washed, autoclaved, saline-suspended staphylococci or streptococci. The most severely affected animals showed a marked decrease in lymphoid tissues and resembled grossly and microscopically animals suffering from the classical runt or wasting disease described by others. The timing of the initial antigenic stimulation was of importance, and animals started on their course of injections at an age of 48 hours or older showed no effect. There was a considerable variation in the severity of the disease within litters and from one litter to another. This variation could not be ascribed to a difference in susceptibility between sexes, since both male and female mice were observed to runt under appropriate conditions. Germ-free ICR mice were much more resistant to the runting phenomenon than conventional animals of the same strain, but could be induced to runt by injection of the staphylococcal vaccine suspended in homologous antiserum. The relationship of the runting phenomenon described here and classical runt disease or runting by adrenal hormones is discussed.

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