Ellipsometry is a non-destructive optical technique that measures the change in polarization state of light upon reflection from or transmission through a sample. It can be used to characterize properties like thickness, composition, and crystallinity of thin films. The document discusses the history and principles of ellipsometry, experimental setups, data analysis techniques using modeling to extract sample properties, and applications in measuring films. Modeling involves using equations to describe light-material interactions and minimizing errors between calculated and measured polarization states.
Optical band gap measurement by diffuse reflectance spectroscopy (drs)Sajjad Ullah
Introduction to Optical band gap measurement
by electronic spectroscopy and diffuse reflectance spectroscopy (DRS) with comparison of the results obtained suing different equation and measurement techniques.
The role of scattering in extinction of light as it passes through media is briefly discussed.
Optical band gap measurement by diffuse reflectance spectroscopy (drs)Sajjad Ullah
Introduction to Optical band gap measurement
by electronic spectroscopy and diffuse reflectance spectroscopy (DRS) with comparison of the results obtained suing different equation and measurement techniques.
The role of scattering in extinction of light as it passes through media is briefly discussed.
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Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
Heterostructures, HBTs and Thyristors : Exploring the "different"Shuvan Prashant
This presentation aims at presenting the concepts of heterostructures : a structure resulting from semiconductors of different band gaps are used to form junctions. These junctions could have interesting effects due the potentials formed by the bands at the interfaces.
Perovskite: introduction, classification, structure of perovskite, method to synthesis, characterization by XRD and UV- vis spectroscopy , lambert beer's law, material properties and advantage and application.
Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
Heterostructures, HBTs and Thyristors : Exploring the "different"Shuvan Prashant
This presentation aims at presenting the concepts of heterostructures : a structure resulting from semiconductors of different band gaps are used to form junctions. These junctions could have interesting effects due the potentials formed by the bands at the interfaces.
Experimental Study of Third Order Nonlinear Absorption in Pure and MG Doped L...ijtsrd
With the discovery of laser in 1960 various nonlinear effect arises, the origin of nonlinear optics lies in the nonlinear response of materials to the incident coherent radiation. Using pulsed Q switched Nd YAG Laser, we have observed the important phenomena i.e. third order nonlinear effect in the LiNbO3 crystals. In present work, I have performed an experiment using simple and sensitive single beam Z scan technique to measure nonlinear absorption in LiNbO3 crystals samples such as pure LiNbO3 crystal, 5mol Mg doped LiNbO3 crystal, and 7mol Mg doped LiNbO3 crystal. Vijay Aithekar | Dr. Vishal Saxana "Experimental Study of Third Order Nonlinear Absorption in Pure and MG Doped Lithium Niobate Crystals" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26370.pdf Paper URL: https://www.ijtsrd.com/physics/engineering-physics/26370/experimental-study-of-third-order-nonlinear-absorption-in-pure-and-mg-doped-lithium-niobate-crystals/vijay-aithekar
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Thermal Tuning of Omni-Directional Reflection Band in Si-Based 1d Photonic Cr...ijrap
The temperature dependence of the omni-directional reflection (ODR) band in a one-dimensional photonicbcrystal is proposed simultaneously considering thermal expansion effect and thermo-optic effect. The structure proposed in this study consists of a periodic arrangement of alternate layers of SiO2 as the material of low refractive index and Si as the material of high refractive index. As the refractive index and thickness of both materials used in this study are modulated by temperature, the ODR band can be tuned as a function of temperature. With the increase of temperature, it is noted that the ODR band shifts towards the longer wavelength region. Also, the ODR band broadens slightly. The ODR band can be tuned by variation in the operating temperature of the structure.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
Similar to Ellipsometry- non destructive measuring method (20)
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Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
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Cell utilize energy in the form of ATP.
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Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
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Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
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introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
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Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
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The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
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Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
2. For the 1st time Paul DRUDE use ellipsometry in 1888
In our LAB
3. Alexandre Rothen Published in 1945 a paper where
the word «Ellipsometer» appears for the 1st time
film thickness within ±0.3A
4. What is Ellipsometry?
A method of probing surfaces with light.
ELLIPSOMETRY is a method based on measurement of the
change of the polarisation state of light after reflection at non
normal incidence on the surface to study.
Why we use
Ellipsometry?
Very sensitive
Highly accurate &reproducible
Non-destructive
Easy and quick measurement
No reference material
necessary
5. What Ellipsometry measures: What we are interested in:
Desired information must
be extracted through a
model based analysis
using equations to
describe interaction of
light and materials
6. Principle Of Ellipsometry
Φ0 : angle of incidence
Δ: relative phase change
Ψ: relative amplitude change
s-plane stands perpendicularly
to the plane of incidence
p-plane stands parallel to the
plane of incidence
7. The Fresnel equations
Ellipsometry measures the complex reflectance ratio
With n0 being air, n0 =1, so n1 is directly related to ellipsometric
angles
9. Null Ellipsometry
By rotating the polarizer it is possible to change the phase
shift between the p- and s-component of the incident light.
The trick is to compensate for the phase shift that will occur at
the surface so that the p- and s-component of the reflected
wave will be again in phase and thus linearly polarized.
10. Spectroscopic Phase-Modulated
Ellipsometry (SPME)
Fused silica bar
MgF2 Rochon prism
Xenon lamp /
spectral range = 190 to
2100 nm
Photomultiplier:
UV-Visible
Photodiode: NIR
11. Advantages of PEM
Wide spectral range coverage
Wide spectral range from the FUV to the NIR is covered without
the need for several hardware configurations, and without
moving any optical elements
Large acceptance angle
The photoelastic modulator optical element has a large
tolerance of the incident angle allowing more simple alignment
of the system.
High Accuracy Measurements for all Values of Psi and
Delta
The phase modulated ellipsometer delivers optimum accuracy
for all values of Ψ and Δ
12. Ellipsometry Data Analysis
n, k, d, adjustment
Instead of
Ψ and Δ,
intensity
is
measured
Dispersion
relations are
used for the
representation
of sample
Minimizing the
Mean-square
deviation Χ2
Thickness
of the film,
Refractive
index,
Extinction
coefficient
Delta Psi software
14. The modulated signal to detector takes the general form as
follows:
I(t) = Io + Is sinΔ(t) + Ic cosΔ(t)
Jones formalism equation
The measurement configuration is chosen for the purpose of
simplifying the calculation of trigonometry functions. In the
present set of measurement,
M = 0°, P = 45°, A = 45°, so that,
Io = 1
Is = sin2ΨsinΔ
Ic = sin2ΨcosΔ
15. Each optical element of the system is represented by a (2x2)
matrix.
Sample Polarizer/Analyzer
Modulator
Rotation matrix to
adjust to proper basis
17. Model contains initial estimates of the parameters
which are then varied to generate a set of calculated
Ψcalc and Δcalc that fits best the measured data.
.
Transparent Materials: Classical, Lorentz, Cauchy
Transparent, Conrady, Hartmann, Schott, Sellmeier
Transparent.
Absorbing, Non Metallic Materials: Cauchy Absorbant,
Sellmeier Absorbant, Tauc-Lorentz, Cody-Lorentz.
Absorbing Semiconductors: Adachi, Afromovitz, Excitonic.
Metals: Drude.
18. Backside reflexion is collected but not interfering with front
side due to loss of coherency
Backside reflexion is not collected because diffusion on rough
side or beam is masked
Model should be in agreement with the experiment
19. Thin film
Substrate
Thin film 50% Void 50% Roughness
Bruggeman Effective
Medium Approximation
(EMA) Model
Thin film
Substrate
Void
Thin film
Substrate
Void
20. Data fitting consists in minimizing the mean-square deviation
Χ2 between calculated and measured ellipsometric parameters
(Ψ and Δ) using different algorithm, e.g. Marquardt –
Levenberg algorithm.
The Mean Square Error (MSE) Χ2 is used to qualify the
difference between the experimental and predicted data.
where σi is the standard deviation of the ith data point
N is the number of data points
Mesi is the ith experimental data point
Thi is the ith calculated data point from assumed theoretical
model
24. References
P. Drude, Ann. d. Physik u. Chemie 39, 481 (1890).
Alexandre Rothen, The Review of Scientific Instruments, Vol. 16, No. 2
(1945).
Nguyen Nang Dinh , Tran Quang Trung,Le Khac Binh, Nguyen Dang
Khoa, Vo Thi Mai Thuan, VNU Journal of Science, Mathematics - Physics 24
16-23 (2008) .
Harland G. Tompkins & Eugene A. Irene, Handbook Of Ellipsometry
(2005).
R.M. A Azzam, N.M. Bashara, Ellipsometry and Polarized Light (1999).
Rudolf Holze, Surface and Interface Analysis: An Electrochemists Toolbox
(2009).
Horiba Scientific, Spectroscopic Ellipsometry Manual.
Gaertner Scientific Corporation, Ellipsometry Manual.
Ramdane Benferhat, Basic Principles of Spectroscopic Ellipsometry and
Photo-Elastic Modulator.
Dietrich R. T. Zahn, Optical Spectroscopies of Thin Films and Interfaces.
J.Ph.PIEL, Introduction to Ellipsometry.
G.E Jellison Jr., Ellipsometry Data Analysis: a Tutorial.
Editor's Notes
He showed that films, a few A thick, covering a polished metallic surface, could be directly detected by measuring the ellipticity of the light after reflection on the surface. If light, linearly polarized in a plane making an angle other than 0° or 90°, with the plane of incidence, impinges on a metallic surface, the reflected light is elliptically polarized. The shape and the orientation of the ellipse depend on the angle of incidence and the optical constants of the metal. When a thin transparent film covers the metallic surface, the parameters of the ellipse are altered, and the magnitudes of the changes are well within the realm of direct measurement.
Rockefeller institute of medical research: monomolecular layers of protien
tan ψ gives exactly the angle of the first diagonal of the rectangle in which the ellipse is enclosed.
cos Δ gives roughly how fat is going to be the ellipse(shape).
different attenuation and phase shift according to the Fresnel equations.
If a mechanical strain is applied to the quartz bar, such as by a piezoelectric transducer attached to the end of the bar, the modulator becomes birefringent (n0 ≠ ne). This means that light travels along one axis faster than the other when passing through it which produces a different phase velocity for each, and a modulated phase shift is induced to the light beam.
birefringence :the splitting of a light ray, generally by a crystal, into two components that travel at different velocities and are polarized at right angles to each other
ZnO films were deposited on glass substrates by a magnetron Rf-sputtering