Dependence of Light-Induced Esr on NitroGen Content in Amorphous Silicon-Nitrogen Alloys

1996 ◽  
Vol 420 ◽  
Author(s):  
Jinyan Zhang ◽  
Toshihiro Ohtsuka ◽  
Minoru Kumeda ◽  
Tatsuo Shimizu
Keyword(s):  
Amorphous Silicon ◽  
Nitrogen Content ◽  
Dangling Bond ◽  
Narrow Component ◽  
Broad Component ◽  
Wide Range ◽  
G Value ◽  
Three Components

AbstractThe LESR signals are observed for the a-Si1-xNx:H samples over a wide range of nitrogen content at 77K. By decomposing the LESR signals using three components, i.e. the neutral Si dangling bond (Do) component, the broad component with a linewidth of 16 G, and the narrow component with a linewidth of 5 G, we find that the three components are observed only in the Si-rich samples. The density of light-induced Do increases with x, whereas the densities of both the narrow and the broad components increase in the range of x≦0.32 and are almost independent of x for larger x. The g-value of the broad components falls down sharply from 2.01 to 2.006 with an increase in x, while the g-value of the narrow component is unchanged and it is around 2.004. All of the three components can be annihilated by sub-gap illumination. The origins of the broad and the narrow components are discussed.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

scholarly journals Rhizobacteria inoculation in maize associated with nitrogen and zinc fertilization at sowing

2021 ◽  
Vol 25 (2) ◽  
pp. 96-100
Author(s):  
Andréia de L. Moreno ◽  
Jorge F. Kusdra ◽  
Angelita A. C. Picazevicz
Keyword(s):  
Bacillus Subtilis ◽  
Nitrogen Content ◽  
Plant Height ◽  
Nitrogen Fertilization ◽  
Azospirillum Brasilense ◽  
Dry Weight ◽  
Stem Diameter ◽  
Wide Range ◽  
Maize Plants ◽  
Total Dry Weight

ABSTRACT Rhizobacteria have a wide range of plant growth-promoting mechanisms of action, making them an alternative and/or complementary biological input for chemical fertilizers. In this respect, the present study aimed to assess growth and nitrogen accumulation in maize plants as a function of Azospirillum brasilense, Bacillus subtilis, zinc and nitrogen application at sowing. The experiment with the ‘AL Bandeirante’ maize variety was conducted in a greenhouse, using a completely randomized design. The treatments were arranged in a 2 x 2 x 2 x 2 factorial scheme, with six repetitions, considering the presence and absence of Azospirillum brasilense (5 g kg-1), Bacillus subtilis (5 mL kg-1) and zinc (20 g kg-1) in the seeds and addition or not of nitrogen (30 kg ha-1) to the soil. The variables assessed were plant height, stem diameter, leaf, stem, shoot, root and total dry weight, and shoot nitrogen content. Nitrogen fertilization in the absence of zinc increased shoot and total dry weight as well as shoot nitrogen content. Zinc applied to the seeds improved the total and stem dry weight of maize plants in the absence of Bacillus subtilis. Inoculation with Azospirillum brasilense and Bacillus subtilis increased the stem diameter and shoot nitrogen content of maize plants when nitrogen fertilization was not performed at sowing. There was no isolated or interaction effect between factors for plant height and root dry weight.

scholarly journals BIG DATA FOR RISK ANALYSIS: THE FUTURE OF SAFE RAILWAYS

2016 ◽  
Author(s):  
Miguel Figueres Esteban
Keyword(s):  
Big Data ◽  
Risk Analysis ◽  
Safety Management ◽  
New Technology ◽  
Data Sources ◽  
Transport Systems ◽  
Text Documents ◽  
Railway Systems ◽  
Wide Range ◽  
Three Components

New technology brings ever more data to support decision-making for intelligent transport systems. Big Data is no longer a futuristic challenge, it is happening right now: modern railway systems have countless sources of data providing a massive quantity of diverse information on every aspect of operations such as train position and speed, brake applications, passenger numbers, status of the signaling system or reported incidents.The traditional approaches to safety management on the railways have relied on static data sources to populate traditional safety tools such as bow-tie models and fault trees. The Big Data Risk Analysis (BDRA) program for Railways at the University of Huddersfield is investigating how the many Big Data sources from the railway can be combined in a meaningful way to provide a better understanding about the GB railway systems and the environment within which they operate.Moving to BDRA is not simply a matter of scaling-up existing analysis techniques. BDRA has to coordinate and combine a wide range of sources with different types of data and accuracy, and that is not straight-forward. BDRA is structured around three components: data, ontology and visualisation. Each of these components is critical to support the overall framework. This paper describes how these three components are used to get safety knowledge from two data sources by means of ontologies from text documents. This is a part of the ongoing BDRA research that is looking at integrating many large and varied data sources to support railway safety and decision-makers.DOI: http://dx.doi.org/10.4995/CIT2016.2016.1825

The Role of Charged Defects In Current Transport Through Hydrogenated Amorphous Silicon Alloys

1998 ◽  
Vol 507 ◽  
Author(s):  
S.P. Lau ◽  
J.M. Shannon ◽  
B.J. Sealy ◽  
J.M. Marshall
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Defect Density ◽  
Current Transport ◽  
Dangling Bond ◽  
Silicon Alloys ◽  
Metal Structures ◽  
Bond State ◽  
Donor States ◽  
Charged Defects

ABSTRACTCurrent transport in metal-semiconductor-metal structures based on amorphous silicon alloys has been studied in relation to the density of dangling bond state defects. The density of defects was changed by varying alloy composition or by current stressing. We show that the change of current-voltage characteristics and activation energy with defect density and the onset of Poole-Frenkel conduction with composition require charged defects. It is found that there are more charged defects in amorphous silicon nitride (a-Si1−xNx:H) than in amorphous silicon carbide (a-Si1−xCx:H). In addition, an excess of negatively charged dangling bond defects compared to positively charged dangling bond defects is observed in a-Si1−xNx:H films. This is attributed to the presence of N4+ act as the donor states in silicon nitride. We find that the density of charged dangling bond defects can be higher than 1019cm−3.

Infrared Electroabsorption Spectra in Amorphous Silicon Solar Cells

1999 ◽  
Vol 557 ◽  
Author(s):  
J. H. Lyou ◽  
Eric A. Schiff ◽  
Steven S. Hegedus ◽  
S. Guha ◽  
J. Yang
Keyword(s):  
Solar Cells ◽  
Infrared Spectrum ◽  
Amorphous Silicon ◽  
Optical Transition ◽  
Silicon Solar Cells ◽  
Reverse Bias Voltage ◽  
Dangling Bond ◽  
Applied Bias ◽  
Infrared Band ◽  
Peak Energy

AbstractWe report measurements of the infrared spectrum detected by modulating the reverse-bias voltage across amorphous silicon pin solar cells and Schottky barrier diodes. We find a band with a peak energy of 0.8 eV. The existence of this band has not, to our knowledge, been reported previously. The strength of the infrared band depends linearly upon applied bias, as opposed to the quadratic dependence for interband electroabsorption in amorphous silicon.The band's peak energy agrees fairly well with the known optical transition energies for dangling bond defects, but the linear dependence on bias and the magnitude of the signal are surprising if interpreted using an analogy to interband electroabsorption. A model based on absorption by defects near the n/i interface of the diodes accounts well for the infrared spectrum.

Heat Transfer Across Crystalline and Amorphous Silicon Surfaces in Contact With Water and the Effects of the Interfacial Liquid Structuring

2018 ◽  
Author(s):  
Luis E. Paniagua-Guerra ◽  
C. Ulises Gonzalez-Valle ◽  
Bladimir Ramos-Alvarado
Keyword(s):  
Heat Transfer ◽  
Amorphous Silicon ◽  
Linear Response Theory ◽  
Silicon Surfaces ◽  
Liquid Interfaces ◽  
Thermal Boundary Conductance ◽  
Wide Range ◽  
Out Of Plane ◽  
Dynamics Simulations ◽  
Solid Liquid

The understanding of nanoscale heat transfer across solid-liquid interfaces poses similar challenges as solid-solid interfaces; however, the higher mobility of liquid particles increases the complexity of this problem. It has been observed that liquid particles tend to form organized structures in the vicinity of solid surfaces; additionally, the formation of such structures has been reported to correlate with heat transfer across interfaces. Classical molecular dynamics simulations were used to investigate the behavior of liquid water in contact with crystalline and amorphous silicon. The in-plane and out-of-plane structure of interfacial water was characterized under different artificial wettability conditions, i.e., the silicon-water interaction potentials were calibrated to reproduce a wide range of wettability conditions. The change in the vibrational density of states was analyzed in order to quantify the mismatch between modes on both sides of the solid-liquid interfaces. Linear response theory was used to calculate the thermal boundary conductance at the different interfaces and a correlation was found between surface chemistry and heat transfer.

Doping Mechanism in Tetrahedral Amorphous Carbon

1997 ◽  
Vol 498 ◽  
Author(s):  
C W Chen ◽  
J Robertson
Keyword(s):  
Amorphous Silicon ◽  
Amorphous Carbon ◽  
Hydrogenated Amorphous Silicon ◽  
Donor Atom ◽  
Dangling Bond ◽  
Coulombic Repulsion ◽  
Tetrahedral Amorphous Carbon ◽  
Total Energies ◽  
Doping Mechanism ◽  
Hydrogenated Amorphous

ABSTRACTDoping in hydrogenated amorphous silicon occurs by a process of an ionised donor atom partially compensated by a charged dangling bond. The total energies of various dopant and dopant/bonding combinations are calculated for tetrahedral amorphous carbon. It is found that charged dangling bonds are less favoured because of the stronger Coulombic repulsion in ta-C. Instead the dopants can be compensated by weak bond states in the lower gap associated with odd-membered π-rings or odd-numbered π-chains. The effect is that the doping efficiency is low but there are not charged midgap recombination centres, to reduce photoconductivity or photoluminescence with doping, as occurs in a-Si:H.

Observation of slow dangling-bond relaxation inp-type hydrogenated amorphous silicon

1995 ◽  
Vol 51 (4) ◽  
pp. 2173-2179 ◽  
Author(s):  
Martin W. Carlen ◽  
Yueqin Xu ◽  
Richard S. Crandall
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Dangling Bond ◽  
Hydrogenated Amorphous

Effect of thermal annealing and nitrogen content on amorphous silicon thin-film crystallization

2007 ◽  
Vol 204 (7) ◽  
pp. 2347-2354 ◽  
Author(s):  
H. Bouridah ◽  
F. Mansour ◽  
R. Mahamdi ◽  
N. Bounar ◽  
P. Temple-Boyer
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Nitrogen Content ◽  
Thermal Annealing ◽  
Silicon Thin Film
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