Analytical Expression for the Imaginary Part of the Dielectric Constant of Microcrystalline Silicon

2013 ◽  
Vol 1 (2) ◽  
pp. 9 ◽  
Author(s):  
C. Summonte ◽  
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Microcrystalline Silicon ◽  
Analytical Expression

scholarly journals Preparation and characterization of polyani-line/polyvinyl alcohol nanocomposite by laser irradiation

2017 ◽  
Vol 6 (4) ◽  
pp. 77
Author(s):  
N A M Shahin ◽  
S Abd El Mongy ◽  
R Kamal ◽  
A B El- Bially ◽  
A A Shabaka ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Polyvinyl Alcohol ◽  
Laser Irradiation ◽  
Imaginary Part ◽  
Electronic Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Nature

Polyaniline (PANI) - Polyvinyl alcohol (PVA) nanocomposite were prepared using laser irradiation method. X-ray diffraction results showed that, (PANI/PVA) nanocomposite exhibited amorphous nature of polymer. The electronic transition will be studied using Ultraviolet-Visible spectrometer (UV-Vis). The real part of dielectric constant (έ) and imaginary part (ε") were studied. Also, the relaxation time was calculated.

Average Dielectric Constant of Coated Spheres: Application to the IR Absorption Spectra of NiO and MgO

1993 ◽  
Vol 47 (8) ◽  
pp. 1203-1208 ◽  
Author(s):  
C. Pecharroman ◽  
T. Gonzalez Carreno ◽  
J. E. Iglesias
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Boundary Value Problem ◽  
Spray Pyrolysis ◽  
Absorption Spectra ◽  
Boundary Value ◽  
Ir Absorption ◽  
Analytical Expression ◽  
Ir Absorption Spectra ◽  
Coated Spheres

An analytical expression has been obtained for the average dielectric constant of a sample consisting of small coated spheres interspersed in a matrix, by solving the static boundary value problem and averaging the values of the electric field and polarization over the whole of the sample. Absorption IR data of MgO and NiO samples of this kind, produced by spray pyrolysis, embedded in a KBr matrix, are presented, and the theory developed is employed to fit the observed spectra.

Anisotropic Optical Properties of 2D Silicon Telluride

MRS Advances ◽  
2020 ◽  
Vol 5 (35-36) ◽  
pp. 1881-1889 ◽  
Author(s):  
Romakanta Bhattarai ◽  
Jiyang Chen ◽  
Thang B. Hoang ◽  
Jingbiao Cui ◽  
Xiao Shen
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Optical Anisotropy ◽  
Optical Measurement ◽  
Computational Study ◽  
Gw Approximation ◽  
Direction Parallel ◽  
New Device ◽  
Out Of Plane ◽  
Potential Applications

ABSTRACTSilicon telluride (Si2Te3) is a silicon-based 2D chalcogenide with potential applications in optoelectronics. It has a unique crystal structure where Si atoms form Si-Si dimers to occupy the “metal” sites. In this paper, we report an ab initio computational study of its optical dielectric properties using the GW approximation and the Bethe-Salpeter equation (BSE). Strong in-plane optical anisotropy is discovered. The imaginary part of the dielectric constant in the direction parallel to the Si-Si dimers is found to be much lower than that perpendicular to the dimers. The optical measurement of the absorption spectra of 2D Si2Te3 nanoplates shows modulation of the absorption coefficient under 90-degree rotation, confirming the computational results. We show the optical anisotropy originates from the particular compositions of the wavefunctions in the valence and conduction bands. Because it is associated with the Si dimer orientation, the in-plane optical anisotropy can potentially be dynamically controlled by electrical field and strain, which may be useful for new device design. In addition, BSE calculations reduce GW quasiparticle band gap by 0.3 eV in bulk and 0.6 eV in monolayer, indicating a large excitonic effect in Si2Te3. Furthermore, including electron-hole interaction in bulk calculations significantly reduces the imaginary part of the dielectric constant in the out-of-plane direction, suggesting strong interlayer exciton effect in Si2Te3 multilayers.

Temperature Dependence of Optical Constants of Silver Film Studied by In Situ Spectroscopic Ellipsometry

2008 ◽  
Vol 55-57 ◽  
pp. 445-448 ◽  
Author(s):  
S. Rojebuathong ◽  
P. Chindaudom ◽  
W. Luangtip ◽  
M. Horphatum ◽  
P. Eiamchai ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Temperature Dependence ◽  
Imaginary Part ◽  
Spectroscopic Ellipsometry ◽  
Silver Film ◽  
Dielectric Constants ◽  
Nitrogen Gas ◽  
Scattering Time ◽  
Ag Film

A silver film was deposited on silicon wafer by DC unbalance magnetron sputtering system. The temperature dependence of the silver film was investigated. The spectroscopic ellipsometry (SE) with the heating of sample stage (HTC100) was employed for the in situ SE measurement under annealing cycles of the sample from room temperature to 300°C in dry nitrogen gas. The results show that the pseudo dielectric constants (<ε1>, < ε2>) of the sample varied with an annealing temperature. The real part of pseudo dielectric constant (<ε1>) of annealed Ag film was slightly changed and the imaginary part (< ε2>) was strongly increased at a photon energy below the optical band gap (3.5-4.5 eV). Furthermore, the pseudo dielectric constant of imaginary part at low energy region was changed due to the enhancement of crystallinity of Ag film at 300°C. All measured SE spectra were fitted by Drude-Lorentz optical model, the scattering time and resistivity were obtained.

The Research on the Dielectric Constant of Polyester Knitted Fabrics

2015 ◽  
Vol 1089 ◽  
pp. 42-45 ◽  
Author(s):  
Yuan Jun Liu ◽  
Xiao Ming Zhao
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Organization Structure ◽  
Good Choice ◽  
Test Method ◽  
Knitted Fabric ◽  
Single Factor ◽  
Knitted Fabrics ◽  
Microwave Absorbing Property ◽  
Absorbing Property

The influence on polyester knitted fabrics’ dielectric constant of each fabric organization structure of knitted fabrics were discussed by a single factor test method, and made a good choice from various polyester knitted fabric knitting parameters so as to the polyester knitted fabric was provided with the maximum real part and imaginary part of the dielectric constant. The results showed that when the structure of polyester knitted fabric was 2+2 rib, polyester knitted fabric had a good microwave absorbing property in these knitting parameters.

scholarly journals Modeling the Bulk and Nanometric Dielectric Functions of Au and Ag

2021 ◽  
Author(s):  
Brahim Ait Hammou ◽  
Abdelhamid El Kaaouachi ◽  
Abdellatif El Oujdi ◽  
Adil Echchelh ◽  
Said Dlimi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Imaginary Part ◽  
Complex Number ◽  
Theoretical Models ◽  
Electronic Transitions ◽  
Experimental Measurements ◽  
Mathematical Functions ◽  
Lorentz Theory ◽  
Critical Model

In this work, we model the dielectric functions of gold (Au) and silver (Ag) which are typically used in photonics and plasmonics. The modeling has been performed on Au and Ag in bulk and in nanometric states. The dielectric function is presented as a complex number with a real part and an imaginary part. First, we will model the experimental measurements of the dielectric constant as a function of the pulsation ω by appropriate mathematical functions in an explicit way. In the second part we will highlight the contributions to the dielectric constant value due to intraband and interband electronic transitions. In the last part of this work we model the dielectric constant of these metals in the nanometric state using several complex theoretical models such as the Drude Lorentz theory, the Drude two-point critical model, and the Drude three-point critical model. We shall comment on which model fits the experimental dielectric function best over a range of pulsation.

scholarly journals Infrared Absorption and Reflection Spectra of Crystalline TCNQ Salts

1989 ◽  
Vol 42 (2) ◽  
pp. 203 ◽  
Author(s):  
Ajay T Oza
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Infrared Absorption ◽  
Reflectance Spectra ◽  
Reflection Spectra ◽  
Reflectance Curve ◽  
The Real ◽  
Broad Maximum ◽  
Absorption Features ◽  
Reflection Characteristics

The polarised absorption and reflectance spectra of the three TCNQ salts pyridinium (TCNQh, triethylammonium (TCNQh and thermally damaged quinolinium (TCNQh indicate that the absorption features are governed by reflection characteristics. The maximum reflectance curve shows a broad minimum which corresponds to a negative dip in the real part of the dielectric constant and a broad maximum in the imaginary part, as calculated using a Kramers-Kronig

scholarly journals Dielectric properties of myoglobin at 10 GHz by microwave cavity perturbation measurements

2010 ◽  
Vol 24 (1-2) ◽  
pp. 143-147 ◽  
Author(s):  
M. Bonura ◽  
G. Schirò ◽  
A. Cupane
Keyword(s):  
Dielectric Constant ◽  
Imaginary Part ◽  
Perturbation Technique ◽  
Resonant Cavity ◽  
Hydration Shell ◽  
Microwave Cavity ◽  
Glass Capillary ◽  
Cavity Perturbation ◽  
Clear Peak ◽  
Microwave Cavity Perturbation

We report on the temperature dependence, at microwave (mw) frequency, of the imaginary part of the dielectric constant (ε″) in myoglobin powder samples with different hydration levels (h). The measurements have been performed by the cavity perturbation technique, in the range of temperature 80–345 K. The sample is located inside a glass capillary along the axis of a cylindrical copper cavity, resonating in the TE011mode at 9.6 GHz, where the mw electric field has a node. By measuring the variation of the quality factor of the resonant cavity, one can extract the imaginary part of the dielectric constant. At temperatures higher than 230 K we observe an evident increase of the dielectric losses with increasing temperature; the effect scales almost linearly with hydration, indicating that it must be attributed to a relaxation of water in the hydration shell of the protein. Furthermore, ath≥0.18, we observe a clear peak in the ε″ vs.Tcurve, that shifts towards lower temperatures upon increasing hydration; this shows that the activation enthalpy of the hydration water relaxation decreases with hydration. More in general, our data show that the technique of microwave cavity perturbation allows one to study the dynamics of water molecules in the hydration shell of proteins and to extend information obtained with dielectric techniques to the mw frequencies.

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