scholarly journals Optimization of the Refractive Index of Antireflection Coatings on Monocrystalline Silicon Solar Cells for Photovoltaic Application

2022 ◽  
Vol 16 (4) ◽  
pp. 68
Author(s):  
Awa Dieye ◽  
El Hadji Abdoulaye Niasse ◽  
Oumar Absatou Niasse ◽  
Alassane Diaw ◽  
Modou Pilor ◽  
...  
Keyword(s):  
Refractive Index ◽  
Silicon Nitride ◽  
Refraction Index ◽  
Antireflection Coatings ◽  
Hydrogenated Silicon ◽  
Photovoltaic Application ◽  
A Value ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Silicon Oxynitrides

In this work, the following materials have been chosen as anti-reflection layer, namely hafnium (HfO2), magnesium fluoride (MgF2), silicon oxynitrides (SiOxNy), silicon oxides (SiOx), silicon nitride (Si3N4) and hydrogenated silicon nitride (SiNx:H). The calculations were made on the basis of values of layer thicknesses and refractive indices that allow the phase and amplitude conditions to be respected and amplitude conditions. Numerical simulations have shown that low reflectivities at the surface of the surface of the plane cell coated with a simple layer, can be obtained. For example, for simple coatings materials based on Si3N4 and HfO2, we obtain a value of reflectivity around 3 and 2 % respectively. The structures with multilayer coatings such as MgF2/SiNx:H/Si, give a reflectivity of around 1 %. Thus, the refraction index of the coating is an important parameter that plays a major parameter that plays a major role in the optical properties of materials. The closer the refractive index is close to the index of the substrate or the layer above the substrate, the higher the reflectivity.

Fluorescent Nanotechnology: An Evolution in Optical Sensors

2020 ◽  
Vol 17 ◽  
Author(s):  
Dilawar Hassan ◽  
Hadi Bakhsh ◽  
Asif M. Khurram ◽  
Shakeel A. Bhutto ◽  
Nida S. Jalbani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Light Emission ◽  
Environmental Contaminants ◽  
Fluorescent Nanoparticles ◽  
Sensing Applications ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Fluorescent Nanomaterials

Background: The optical properties of nanomaterials have evolved enormously with the introduction of nanotechnology. The property of materials to absorb and/or emit specific wavelength has turned them into one of the most favourite candidates to be effectively utilized in different sensing applications e.g organic light emission diodes (OLEDs) sensors, gas sensors, biosensors and fluorescent sensors. These materials have been reported as a sensor in the field of tissue and cell imaging, cancer detection and detection of environmental contaminants etc. Fluorescent nanomaterials are heling in rapid and timely detection of various contaminants that greatly impact the quality of life and food, that is exposed to these contaminants. Later, all the contaminants have been investigated to be most perilous entities that momentously affect the life span of the animals and humans who use those foods which have been contaminated. Objective: In this review, we will discuss about various methods and approaches to synthesize the fluorescent nanoparticles and quantum dots (QDs) and their applications in various fields. The application will include the detection of various environmental contaminants and bio-medical applications. We will discuss the possible mode of action of the nanoparticles when used as sensor for the environmental contaminants as well as the surface modification of some fluorescent nanomaterials with anti-body and enzyme for specific detection in animal kingdom. We will also describe some RAMAN based sensors as well as some optical sensing-based nanosensors. Conclusion: Nanotechnology has enabled to play with the size, shape and morphology of materials in the nanoscale. The physical, chemical and optical properties of materials change dramatically when they are reduced to nanoscale. The optical properties can become choosy in terms of emission or absorption of wavelength in the size range and can result in production of very sensitive optical sensor. The results show that the use of fluorescent nanomaterials for the sensing purposes are helping a great deal in the sensing field.

scholarly journals Electrical breakdown of amorphous hydrogenated silicon rich silicon nitride thin film diodes

1996 ◽  
Vol 43 (9) ◽  
pp. 1592-1601 ◽  
Author(s):  
S.J. Bijlsma ◽  
H. van Kranenburg ◽  
K.J.B.M. Nieuwesteeg ◽  
M.G. Pitt ◽  
J.F. Verweij
Keyword(s):  
Thin Film ◽  
Silicon Nitride ◽  
Electrical Breakdown ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon

scholarly journals 29Si NMR Chemical Shifts in Crystalline and Amorphous Silicon Nitrides

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1646 ◽  
Author(s):  
Ilia Ponomarev ◽  
Peter Kroll
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Density Functional ◽  
Chemical Shifts ◽  
29Si Nmr ◽  
Hydrogenated Silicon ◽  
Nmr Chemical Shifts ◽  
Nmr Data ◽  
29Si Nmr Spectra ◽  
The Impact

We investigate 29Si nuclear magnetic resonance (NMR) chemical shifts, δiso, of silicon nitride. Our goal is to relate the local structure to the NMR signal and, thus, provide the means to extract more information from the experimental 29Si NMR spectra in this family of compounds. We apply structural modeling and the gauge-included projector augmented wave (GIPAW) method within density functional theory (DFT) calculations. Our models comprise known and hypothetical crystalline Si3N4, as well as amorphous Si3N4 structures. We find good agreement with available experimental 29Si NMR data for tetrahedral Si[4] and octahedral Si[6] in crystalline Si3N4, predict the chemical shift of a trigonal-bipyramidal Si[5] to be about −120 ppm, and quantify the impact of Si-N bond lengths on 29Si δiso. We show through computations that experimental 29Si NMR data indicates that silicon dicarbodiimide, Si(NCN)2 exhibits bent Si-N-C units with angles of about 143° in its structure. A detailed investigation of amorphous silicon nitride shows that an observed peak asymmetry relates to the proximity of a fifth N neighbor in non-bonding distance between 2.5 and 2.8 Å to Si. We reveal the impact of both Si-N(H)-Si bond angle and Si-N bond length on 29Si δiso in hydrogenated silicon nitride structure, silicon diimide Si(NH)2.

scholarly journals Equivalence between positive and negative refractive index materials in electrostatic cloaks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xingcai Li ◽  
Juan Wang ◽  
Jinghong Zhang
Keyword(s):  
Refractive Index ◽  
Negative Refraction ◽  
Negative Refractive Index ◽  
Analytical Formula ◽  
Refraction Index ◽  
Dielectric Materials ◽  
Static Field ◽  
Colloid Science ◽  
Negative Refraction Index ◽  
Equivalence Relationship

AbstractWe investigate, both theoretically and numerically, the equivalence relationship between the positive and negative refraction index dielectric materials in electrostatic invisibility cloak. We have derived an analytical formula that enables fast calculate the corresponding positive dielectric constant from the negative refraction index material. The numerical results show that the negative refraction index material can be replaced by the positive refractive index materials in the static field cloak. This offers some new viewpoints for designing new sensing systems and devices in physics, colloid science, and engineering applications.

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