FDTD Simulation of Light Propagation Inside a-Si:H Structures

2010 ◽  
Vol 1245 ◽  
Author(s):  
Alessandro Fantoni ◽  
Pedro Pinho
Keyword(s):  
Light Absorption ◽  
Electromagnetic Waves ◽  
Light Propagation ◽  
Light Transmission ◽  
Visible Spectrum ◽  
Propagation Model ◽  
Interface Roughness ◽  
Fdtd Simulation ◽  
Doping Density ◽  
Surface And Interface

AbstractWe have developed a computer program based on the Finite Difference Time Domain (FDTD) algorithm able to simulate the propagation of electromagnetic waves with wavelengths in the range of the visible spectrum within a-Si:H p-i-n structures. Understanding of light transmission, reflection and propagation inside semiconductor structures is crucial for development of photovoltaic devices. Permitting 1D analysis of light propagation over time evolution, our software produces results in well agreement with experimental values of the absorption coefficient. It shows the light absorption process together with light reflection effects at the incident surface as well as at the semiconductor interfaces. While the effects of surface reflections are easily taken into account by the algorithm, light absorption represents a more critical point, because of its non-linear dependence from conductivity. Doping density, density of states and photoconductivity calculation are therefore crucial parameters for a correct description of the light absorption-transmission phenomena through a light propagation model.The results presented in this paper demonstrate that is possible to describe the effect of the light-semiconductor interaction through the application of the FDTD model to a a-Si:H solar cell. A more general application of the model to 2D geometries will permit the analysis of the influence of surface and interface roughness on the device photovoltaic efficiency.

scholarly journals Deep Subwavelength Power Concentration-Based Hyperbolic Metamaterials

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Amanpreet Kaur ◽  
Saptarshi Banerjee ◽  
Wangshi Zhao ◽  
Jayanti Venkataraman ◽  
Zhaolin Lu
Keyword(s):  
Electromagnetic Waves ◽  
Light Propagation ◽  
Spot Size ◽  
Diffraction Limit ◽  
Evanescent Waves ◽  
Hyperbolic Metamaterials ◽  
Preferred Direction ◽  
Propagating Waves ◽  
Medium Design ◽  
Collimated Beam

Hyperbolic metamaterials can manipulate electromagnetic waves by converting evanescent waves into propagating waves and thus support light propagation without diffraction limit. In this paper, deep subwavelength focusing (or power concentration) is demonstrated both numerically and experimentally using hyperbolic metamaterials. The results verify that hyperbolic metamaterials can focus a broad collimated beam to spot size of ~λ0/6 using wired medium design for both normal and oblique incidence. The nonmagnetic design, no-cut-off operation, and preferred direction of propagation in these materials significantly reduce the attenuation in electromagnetic waves.

scholarly journals LIQUID LIGHT FILTER FOR THE VISIBLE SPECTRUM BASED ON HYDROPHILIC SOLUTIONS

2021 ◽  
Vol 6 ◽  
pp. 225-229
Author(s):  
Konstantin S. Nikitin ◽  
Victor S. Efremov
Keyword(s):  
Light Transmission ◽  
Visible Spectrum ◽  
Light Filter ◽  
Principal Possibility

The principal possibility of designing a liquid light filter using hydrophilic solutions is considered. Search for hydrophilic solutions with the most uniform light transmission at all wavelengths of the visible spectrum.

scholarly journals Study Effect of Objects Orientation in the Mediums On GPR Signal Reflections Using FDTD Simulation

2018 ◽  
Vol 3 (11) ◽  
pp. 73-77
Author(s):  
Aye Mint Mohamed Mostapha ◽  
Gamil Alsharahi ◽  
Abdellah Driouach
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Ground Penetrating Radar ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Ground Surface ◽  
Propagation Path ◽  
Fdtd Simulation ◽  
Ground Penetrating ◽  
Dielectric Objects

Ground penetrating radar (GPR) is a very effective tool for detecting and identifying objects below the ground surface.  based on  the propagation and reflection of high-frequency electromagnetic waves. The GPR reflection can be affected by many things like the type of objects orientation, their shapes ..ect. The purpose of this paper is to  study by simulation the effect of objects orientation in two different mediums (dry and wet sand) on the GPR signal reflection using Reflexw software which is based on a numerical method known as finite difference in time domain (FDTD).  The simulations that have been realized included a conductor  and dielectric objects. The results obtained have led us to find that the propagation path, the reflection strength and the signal form change with the change of object orientation and nature. To confirm the validity of the results, we compared them with experimental results previously published by researchers under the same conditions.

Surface and Interface Roughness of Ultrathin Nitric Oxide Oxynitride Gate Dielectric

1998 ◽  
Vol 145 (1) ◽  
pp. L13-L15 ◽  
Author(s):  
Rama I. Hegde ◽  
Bikas Maiti ◽  
Raghaw S. Rai ◽  
Kimberly G. Reid ◽  
Philip J. Tobin
Keyword(s):  
Nitric Oxide ◽  
Gate Dielectric ◽  
Interface Roughness ◽  
Surface And Interface

scholarly journals Analysis of the Light Propagation Model of the Optical Voltage Sensor for Suppressing Unreciprocal Errors

Sensors ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 85 ◽  
Author(s):  
Hui Li ◽  
Zhida Fu ◽  
Liying Liu ◽  
Zhili Lin ◽  
Wei Deng ◽  
...  
Keyword(s):  
Light Propagation ◽  
Voltage Sensor ◽  
Propagation Model

scholarly journals A light-propagation model for aircraft trajectory planning

2012 ◽  
Vol 56 (3) ◽  
pp. 873-895 ◽  
Author(s):  
Nourelhouda Dougui ◽  
Daniel Delahaye ◽  
Stéphane Puechmorel ◽  
Marcel Mongeau
Keyword(s):  
Trajectory Planning ◽  
Light Propagation ◽  
Propagation Model ◽  
Aircraft Trajectory

Thermal Degradation of SiGe Interfaces Studied by X-Ray Reflectivity and Diffraction

1991 ◽  
Vol 239 ◽  
Author(s):  
J. M. Hudson ◽  
A. R. Powell ◽  
D. K. Bowen ◽  
M. Wormington ◽  
B. K. Tanner ◽  
...  
Keyword(s):  
Short Range ◽  
Grazing Incidence ◽  
Sige Layer ◽  
Interface Roughness ◽  
Total Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface And Interface ◽  
Superlattice Structures

ABSTRACTWe demonstrate the use of x-ray diffraction to provide accurate compositional information, together with grazing incidence reflectivity to provide information on layer thicknesses and surface and interface roughnesses, on Si/Si1-xGex superlattice structures of less than 200nm total thickness.The quality of SiGe interfaces has been investigated in superlattices where x varies from 0.1 to 0.5. At low Ge compositions the interfaces are shown to be smooth to a few angstroms. However, as the Ge composition in the SiGe layer approaches 50%, severe roughness is observed at the SiGe to Si interfaces, although the Si to SiGe interfaces remain relatively smooth.Upon annealing for one hour at 850°C the Ge diffuses outwards from the SiGe layers and can be closely modelled by inclusion of a (2.4±0.3)nm linearly graded layer either side of the SiGe layer into a simulation program. The long range roughness at the SiGe to Si interface is lost upon annealing leaving only a short range roughness of similar size to the Si to SiGe interface roughness.Reflectivity measurements have been shown to distinguish between interface roughness and interdiffusion for the annealed system.

scholarly journals COSMOLOGICAL CONSTANT AND THE SPEED OF LIGHT

2001 ◽  
Vol 10 (01) ◽  
pp. 41-48 ◽  
Author(s):  
W. R. ESPÓSITO MIGUEL ◽  
J. G. PEREIRA
Keyword(s):  
Gravitational Field ◽  
Cosmological Constant ◽  
Electromagnetic Waves ◽  
Light Propagation ◽  
Wave Optics ◽  
Speed Of Light ◽  
Positive Cosmological Constant ◽  
Velocity Of Light ◽  
Refractive Medium ◽  
The Relationship

By exploring the relationship between the propagation of electromagnetic waves in a gravitational field and the light propagation in a refractive medium, it is shown that, in the presence of a positive cosmological constant, the velocity of light will be smaller than its special relativity value. Then, restricting again to the domain of validity of geometrical optics, the same result is obtained in the context of wave optics. It is argued that this phenomenon and the anisotropy in the velocity of light in a gravitational field are produced by the same mechanism.

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