The document discusses the electro-optical properties of semiconductors under an applied electric field. It describes the Franz-Keldysh effect where an electric field causes a red shift and broadening of the band edge absorption in bulk semiconductors. It also discusses the Stark effect which modifies the excitonic absorption due to changes in the electron-hole interaction. When applied to quantum wells, the electric field can cause a quantum-confined Stark effect or quantum-confined Franz-Keldysh effect, broadening excitonic resonances and allowing forbidden transitions.
Describes Fiber Optics using Optical Ray Theory.
For comments please contact me at solo.hermelin@gmail.com.
For more presentations visit my website at http://www.solohermelin.com.
Presentation of third- and fifth-order optical nonlinearities measurement using the D4Sigma-Z-scan Method. I present a resolution of propagation equation in general case (with third- and fifth-order nonlinearities) and a numerical inversion.
This presentation is conclude with experimental results.
Describes Fiber Optics using Optical Ray Theory.
For comments please contact me at solo.hermelin@gmail.com.
For more presentations visit my website at http://www.solohermelin.com.
Presentation of third- and fifth-order optical nonlinearities measurement using the D4Sigma-Z-scan Method. I present a resolution of propagation equation in general case (with third- and fifth-order nonlinearities) and a numerical inversion.
This presentation is conclude with experimental results.
The attached narrated power point presentation offers a block level and an elementary level mathematical treatment of optical communication systems employing coherent detection. The material will immensely benefit KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
Measurement of optical fiber refractive indexCKSunith1
The attached narrated power point presentation discusses the various methods for measurement of refractive index of an optical fiber. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
In radio and electronics, an antenna is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
Laser diode have to have a specific architecture in order to optimize the laser light leaving the waveguide. There are various factors that are to be precisely noted and put into certain equations in order to calculate the differential quantum efficiency and to improvise the design of the diode lasers. The slides explain about reservoir analogy, threshold and gain and photon density as well as carrier density rate equations. Glad if it helps :)
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 attached narrated power point presentation offers a block level and an elementary level mathematical treatment of optical communication systems employing coherent detection. The material will immensely benefit KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
Measurement of optical fiber refractive indexCKSunith1
The attached narrated power point presentation discusses the various methods for measurement of refractive index of an optical fiber. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
In radio and electronics, an antenna is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
Laser diode have to have a specific architecture in order to optimize the laser light leaving the waveguide. There are various factors that are to be precisely noted and put into certain equations in order to calculate the differential quantum efficiency and to improvise the design of the diode lasers. The slides explain about reservoir analogy, threshold and gain and photon density as well as carrier density rate equations. Glad if it helps :)
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.
Electronic bands structure and gap in mid-infrared detector InAs/GaSb type II...IJERA Editor
We present here theoretical study of the electronic bands structure E (d1) of InAs (d1=25 Å)/GaSb (d2=25 Å) type
II superlattice at 4.2 K performed in the envelope function formalism. We study the effect of d1 and the offset ,
between heavy holes bands edges of InAs and GaSb, on the band gap Eg (), at the center of the first Brillouin
zone, and the semiconductor-to-semimetal transition. Eg (, T) decreases from 288.7 meV at 4.2 K to 230 meV
at 300K. In the investigated temperature range, the cut-off wavelength 4.3 m ≤ c ≤ 5.4 m situates this sample
as mid-wavelength infrared detector (MWIR). Our results are in good agreement with the experimental data
realized by C. Cervera et al.
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.
Abstract: In this paper circuit for coilgun is simulated and analyzed using SIMULINK. Behavior of the magnetic field due to the current carrying coil is analyzed. Also, the effect on the coilgun performance for different weights of projectiles is investigated. The speed profile for different positions of the projectile is observed which is a critical parameter for coilgun operation. A comparison is drawn between the simulated and experimental results.
Горбунов Н.А., Государственная морская академия им. С.О. Макарова, г. Санкт-Петербург
Разработка плазменных технологий для прямого фотоэлектрического преобразования с сфокусированного солнечного излучения
NS2 installation guideline for the student to install the software . It use for student to install and download the software. The software is about the experimental of communication technology.
Similar to Electro optical properties of semiconductor optics (20)
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Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
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Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
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CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
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An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
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More examples of our work https://www.r-r-consult.dk/en/cases-en/
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Electro optical properties of semiconductor optics
1. Chapter 10
Electro-Optical properties of Semiconductors
Introduction to the Semiconfductor Optics
1/18 Quantum Functional Material & Device Lab.
21-5-2019
Presented by
P. Kedhareswara Sairam
2. 1.Franz-Keldysh effect
2. DC Stark effect
3.Electric Field Effect in Two Dimensions
Quantum-Confined Franz-Keldysh and
Quantum-Confined Stark effect
2/18 Quantum Functional Material & Device Lab.
Introduction
3. 3/18 Quantum Functional Material & Device Lab.
Effect of electric filed on optical interband transition in semiconductors by ignoring columbic interaction.
Broadening and low energy shift to the band edge absorption spectra and red shift towards low energies.
Change in the e-h columbic interaction due to e field and its free carrier absorption.
Oscillatory structure, and broadening splitting in addition to the broadening shifting and absorption
coefficients .
Application of electric field over the bulk semiconductor and interaction of Hamiltonian due to e field.
Application of electric field with e-h pairs (DC-Stark effect).
Effect of field ionization and (Uncertainty principle) life time of excition, and calculated absorption coefficients
effects of different excitons spectra with increase in field magnitude and changes in absorption.
Electric field in 2-D
Quantum-Confined Franz-Keldysh and
Quantum-Stark effect.
Outline
4. The Schrodinger equation for the above Hamiltonian
4/18 Quantum Functional Material & Device Lab.
Application electric field over bulk semiconductor leads to motion of
electron through lattice associated with interaction Hamiltonian
Total Hamiltonian of e-h pair in uniform electric field is given by
Relative coordinate eqn of field
Assuming electron is moving in the Z direction Calculated absorption coefficient
1.FRANZ-KELDYSH EFFECT
Here is the eigen function εn
indicates the energy eigen values for
relative motion and mr and Φn are the
reduced mass of e-h pair and eigen
function.
He
int is Hamiltonian of electric field.
5. 5/18 Quantum Functional Material & Device Lab.
The final calculated absorption spectra for direct-allowed transitions.
Where ε/and Ai is the Airy function given as
Calculated free-carrier absorption with zero
field and field of 105 V/cm for abulk
semiconductor is given in the Fig 10.1
Airy function shows two types of properties that decaying
exponentially for positive valus and oscillatory motion for
negative values.
Amplitude of oscillations decreased with in creased in ℏ𝜔
Shift towards the lower energies
called the red shift which can be
explained by photon assisted
tunneling.
6. 6/18 Quantum Functional Material & Device Lab.
Field induced tunneling of an electron from VB to CB
Fig.(a) without field
Fig.(b) due to electric field tilts the electron states in
direction for both the bands.
Band edge absorption of semiconductors in the
absence of columbic interaction leads to the
appearance of absorption below the bandgap and to o
oscillatory absorption variations for energies above
the gap.
Free carrier absorption in electric field is often called Franz-Keldysh
electroabsorption
Fig.10.2
7. 7/18 Quantum Functional Material & Device Lab.
Improving bandgap analysis by including the columbic
interaction between the e and h in a bulk semiconductor.
The combined potential of e-h pair with e field is given by
is plotted between the potential and Z
direction
a. Major effect is modification of purely attractive columb wellin
to apotential barrier due the field.
b. Field ionization decreases the life time of exciton leads to the
broadening of resonances (Uncertainty principle) and also
widening of potential well resulting in a red shifting of
excitonic lines.
c. Second order effect of shift is known as dc –Stark effect.
2.DC Stark effect
Fig.10.3
8. The Schrodinger equation by replacing the potential term
Solution of this eqn
Where
Eqn 10.6 - Shows the enhancement of the free
carrier Franz-Keldysh absorption due o the e-h
Columb attraction
The electric field energy should provide which is at
least equal to the binding energy of exciton across
the Bhor radius.
The ionization field is about 5x103 V/cm in GaAs
EB –Binding energy
aB- Bhor radius of the excitons
8/18 Quantum Functional Material & Device Lab.
9. 9/18 Quantum Functional Material & Device Lab.
• As the electric field increases , the
excitons shifts towards lower energies
and broadens.
• If the field strength is increased to
ionization , the bound exicton level
becomes broadened and mixed with
continuum.
• Here the shift is relatively small and
broadening usually dominates the
spectra.
For exciton n=2 corresponds to degenerated S-like and P-like.
In addition to the Stark Shifting also we have Stark splitting of degenerate
exciton states.
For n=2 the p exciton is forbidden and s exciton is allowed, due to the Crystal
inversion symmetry from Ch.4
Fig.10.4
10. 10/18 Quantum Functional Material & Device Lab.
• The field along the Z direction leads to a
combination of s and pz results to be in the
form of doublet in the absorption spectrum.
• Here also we can observe the broadening
and shifting as increase in field.
Fig.10.6
Shows the calculated elctroabsorption for a temaparture-
brodended exciton and continuum states at different field
magnitudes.
Also shows the oscillations on the high energy side of the
exciton as well as broadening and shifting.
Fig.10.5
11. 11/18 Quantum Functional Material & Device Lab.
Displays the elctroabsorption coefficient of PbI2 ,with
and without field, and the absorption difference Δα.
The experimental theories are in good agreement with
theory of excitonic effects.
Fig.10.8
Shows the change in absorption spectra with and without an
electric field of 2.85 X 105 V/cm in comparison to excitonic
absorption and free carrier absorption theories
Fig.10.7
12. 12/18 Quantum Functional Material & Device Lab.
Shows the changes in GaAs, induced by various field
strength also about the oscillatory structure in Δn( 𝜔).
Important note that changes in
electroabsorption ,discussed so far gives rise to the
refractive index changes .In the vicinity of the
bandgap energy through the Kramers - Kronig
transformation.
It will changes in the few orders of the percentages
with the applied field magnitude of ~ 105 V/cm
Fig. 10.9
13. 13/18 Quantum Functional Material & Device Lab.
3.Electric Field Effect in Two Dimensions
Quantum-Confined Franz-Keldysh and
Quantum-Confined Stark effect
Considering the quasi 2D GaAs-AlxGa1-xAs MQWs and study
about the optical properties in the presence of electric field.
Applied field may be both in Parallel and perpendicular to the
quantum wells layers.
The main effect of field is broadening and exciton resonance
Fig10.10 shows EA spectra for the 3 field magnitudes applied
parallel to the GaAs-AlxGa1-xAs MQWs layers.
Exicton in MQWs having large binding energy than bulk,
consequently are not easy to ionize.
Effect of field perpendicular to the layers in MQWs, where e-h Coulomb interaction is neglected ,leads
to the EA spectra May be descried as Quantum Confined Franz-Keldysh effect.
Where as with Coulomb interaction spectra referred to as Quantum Confined Stark effect.
14. 14/18 Quantum Functional Material & Device Lab.
Shows the modified energy levels and wave
function for the e and h in an infinite dep
potential well.
QWs are distorted by the field as shown in
the fig.
The field pushes the e and h in the opposite
walls of well.
The field ionization of exciton is inhibited in
2D by the walls of QW where it is dominated
in 3D bulk materials.
Hence the exciton shifts and persist up to
high fields.
Fig.10.11
15. 15/18 Quantum Functional Material & Device Lab.
Displays the observed large red shift of the excitonic peak.
The exciton persists for field strength as high as 1.8 X 105
V/cm (20V)
In experiment using two 94 A0 GaAs QW centered in
superlattice, in the perpendicular fields.
Opposite to the behavior of Fig.10.11.
One more consequence is lowering of symmetry and thus
removal of strict transition rules for
a. The allowed transitions are those between e and h confined states with Δj = 0.
b. The transitions with Δj ‡ 0 are forbidden in the absence of external field.
c. The transitions with Δj ‡ 0 are allowed due to the e and h wave functions are
overlap and is generally zero for i ‡ j
Fig.10.12
16. 16/18 Quantum Functional Material & Device Lab.
Shows the observed forbidden transitions and their
enhancement with larger field.
The subscript letters l and h, refer as light and heavy hole
states
The allowed transitions in the absence of electric field are
The transitions are forbidden
that have become as allowed due the electric field.
The consequences of the forbidden transitions in the EA
of the MQWs has derived by using sum rules for the
interband transitions
It states that, increase of absorption at heigher photon
energiesis acompained by the reduction of peak of the
allowed transition at low photon energies.
Fig.10.13
17. 17/18 Quantum Functional Material & Device Lab.
Summary
Electric field effects on electro-absorption coefficients in Bulk semiconductors.
Electric field induced changes of optical spectra near band edge.
Role of excitons in variation of field magnitudes.
Exciton Stark shifting, Stark splitting.
Broadening and red shift and Franz-Keldysh oscillations.
Electric field effects in 2D Multi Quantum Wells.
QCSC and QCFK.