Exciton spectroscopy
|
|
|
- John Harvey
- 6 years ago
- Views:
Transcription
1 Lehrstuhl Werkstoffe der Elektrotechnik Exciton spectroscopy in wide bandgap semiconductors Lehrstuhl Werkstoffe der Elektrotechnik (WW6), Universität Erlangen-Nürnberg, Martensstr. 7, Erlangen Vortrag auf der WET- in Februar 2009
2 Lehrstuhl Werkstoffe der Elektrotechnik Exciton spectroscopy in wide bandgap semiconductors 1. Exciton theory Wannier-Mott excitons, Frenkel excitons impurity bound excitons 2. Measurement techniques Optical absorption PL/CL, PL-E, TRPL 3. Exciton spectra Features in wide bandgap semiconductors Application to materials science 4. Summary
3 The exciton concept Exciton: electron-hole pair Attraction by Coulomb forces: 2 e U r 4 r 0 r e and h recombine when they meet, thus * finite lifetime (ps µs range) * e and h must have same group velocity E v k (valid e.g. for k 0) ~ k Exciton: particle of quantum mechanics neutral (no charge) free movement in the lattice effective mass m +m may interact with other particles (e.g. photons) is a boson (integer spin number) ½ r e h Excitons form in 1. Theory WET- semiconductors, insulators and molecular crystals.
4 Exciton formation energy 1. Theory WET- Treatment analog to hydrogen or positronium: Bohr-Rutherford model one particle orbits around the other particle Formation energy*: n: quantum number (n = 1: ground state) E n e r n me mh me mh reduced mass Energy + Position in the bandgap: free electron and hole: conduction band edge Eg exciton levels in the upper band gap Eg E n E g 0 conduction band valence band... E E E g E E g E E E g 4 g exciton levels * Formation energies are negative (add a minus sign), but as they are subtracted from the conduction band edge, they are treated positive within this talk.
5 Exciton formation energy Treatment analog to hydrogen or positronium: Bohr-Rutherford model one particle orbits around the other particle Formation energy: n: quantum number (n = 1: ground state) Eg E n E n e r n Position in the bandgap: free electron and hole: conduction band edge Eg exciton levels in the upper band gap 1. Theory WET-
6 Wannier-Mott exciton Dielectric medium approach (Wannier-Mott exciton) E n Hydrogen: e r n Semiconductor: Bohr-Radius 4 m ; 1 e r H Atom ev E1 13, 6 E 1 r n 0,1 m ; 10 e some 10 mev 2 2 n h 0 2 m e r r Cu O (77 K) 2 1. Theory WET- r = atomic distances! 1 free exciton E = 2,17 ev; = 10; µ eff 0,7 g E = 100 mev/n² n r [Kittel]
![Frenkel exciton Typical exciton formation energies [mev] 1.](/docs-images/77/76091573/images/7-0.jpg "Theory WET- Frenkel exciton strong bonding to crystal lattice but: wave with translational symmetry may move freely in the lattice!")
7 Frenkel exciton Typical exciton formation energies [mev] 1. Theory WET- Frenkel exciton strong bonding to crystal lattice but: wave with translational symmetry may move freely in the lattice! [Kittel] Wannier-Mott and Frenkel excitons: two extremes of the same phenomenon [Kittel]
8 Frenkel exciton 1. Theory WET- Frenkel exciton models ground state of a potential well collective excitation bound to an atom (like a phonon or a spin wave) + E = 0! Frenkel excitons are observed in Alkali halides Rare gas crystals (organic) molecular crystals Kr (20 K) E E g 11,7 ev 1,5 ev E 1 g E 1 Alkali halide crystals Excitons localized at anions, because anions have deeper excitation levels. [Kittel]
9 Bound excitons in semiconductors Donor bound exciton (D,X) 0 Acceptor bound exciton (A,X) Exciton is localized on an impurity, (still extends ~10 atomic distances) Binding energy: D 0.1 x impurity ionization energy 0 exciton levels at E 0 g E D 0 Properties of bound excitons bound exciton 3 exciton lifetime ~ E 2 ex D 0 in wide bandgap semiconductors, E n< D0 free excitons vanish at higher temperatures n higher (excited) states exist, but cannot be trated by the Wanier-Mott model anymore Excitons can be bound to any donor or acceptor in the material! excitons bound to ionized impurities may also exist + 1. Theory WET-
10 Bound excitons in semiconductors Donor bound exciton (D,X) 0 Acceptor bound exciton (A,X) Exciton is localized on an impurity, (still extends ~10 atomic distances) Binding energy: D 0.1 x impurity ionization energy 0 exciton levels at E 0 g E n D 0 higher (excited) states exist, but cannot be trated by the Wanier-Mott model anymore + 1. Theory WET- Wannier Mott Impurity bound Frenkel E1 E1 E1 In semiconductors, only free and impurity bound excitons exist.
11 Optical absorption 2. Measurement techniques WET- GaAs, 21 K h h E E g g E 1 fundamental absorption (generation of e and h) excitonic absorption (generation of free excitons) [Kittel]
12 Recombinative luminescence Optical emission due to optical or electron excitation at (radiative recombination spectroscopy) h E g Photoluminescence (PL) fixed incident photon energy, variable energy detection PL excitation (PLE) altering incident energy fixed detection energy time resolved PL (TRPL) pulsed excitation, measure rise and decay of a fixed detection energy 2. Measurement techniques WET- [
13 Recombinative luminescence Optical emission due to optical or electron excitation at (radiative recombination spectroscopy) h E g 2. Measurement techniques WET- Photoluminescence (PL) fixed incident photon energy, variable energy detection PL excitation (PLE) altering incident energy fixed detection energy time resolved PL (TRPL) pulsed excitation, measure rise and decay of a fixed detection energy most excited electrons and holes will relax into ground states before recombination excite at energies of higher states and detect ground state luminescence evaluate exciton lifetimes and different decay channels
14 Temperature dependence 3. Exciton spectra WET- Bound excitons (at Eg En D 0 ) dominate tow temperature spectra Free excitons (at Eg E n ) dominate high temperature spectra Excitons at higher states are only visible in high-quality material at very low temperatures E < D n 0 AlN 293 K Increasing temperatures... lead to peak broadening shift the bandgap according to E T E 0 g g 2 T T AlN: D0 30 mev E 49 mev 1 10 K [Prinz07]
15 Valence band splitting 3. Exciton spectra WET- Crystal field splitting cr due to crystal symmetry Spin-orbit splitting so due to electron-atom interaction Different endpoints of electron-hole recombination leads to different transitions of free/bound excitons. The same happens if the symmetry is lowered by strain (heteroepitaxy, strained layers). Selection rules: Intensities depend on polarisation of the incident light. AlN (schematic) [Li 2003]
16 Valence band splitting 3. Exciton spectra WET- Crystal field splitting cr due to crystal symmetry Spin-orbit splitting so due to electron-atom interaction Different endpoints of electron-hole recombination leads to different transitions of free/bound excitons. X A X B X C The same happens if the symmetry is lowered by strain (heteroepitaxy, strained layers). Selection rules: Intensities depend on polarisation of the incident light. AlN (schematic) [Li 2003]
17 Valence band splitting 3. Exciton spectra WET- Crystal field splitting cr due to crystal symmetry Spin-orbit splitting so due to electron-atom interaction Different endpoints of electron-hole recombination leads to different transitions of free/bound excitons. 0 (D,X A) 0 (D,X B) 0 (D,X ) C The same happens if the symmetry is lowered by strain (heteroepitaxy, strained layers). Selection rules: Intensities depend on polarisation of the incident light. AlN (schematic) [Li 2003]
18 Valence band splitting 3. Exciton spectra WET- Crystal field splitting cr due to crystal symmetry Spin-orbit splitting so due to electron-atom interaction Different endpoints of electron-hole recombination leads to different transitions of free/bound excitons. The same happens if the symmetry is lowered by strain (heteroepitaxy, strained layers). Selection rules: Intensities depend on polarisation of the incident light. AlN (schematic) [Ibach-Lüth]
19 Phonon interaction 3. Exciton spectra WET- Phonon-assisted recombination Emission of (different) phonons lowers the transition energy single/multi-phonon replica TA = 46, 51 mev LA = 77 mev TO = 95, 96 mev LO = 104, 107 mev 6H-SiC, 10 K (almost) no zero-phonon lines of free excitons in indirect semiconductors (conservation of momentum) for bound excitons k 0 is partly relaxed by localisation (Heisenberg uncertanity) 6H-SiC: D0 16, 30, 32 mev E 30 mev 1 (P, R, S of Nitrogen donor) [Peppermüller]
20 Complex spectra 3. Exciton spectra WET- Recombination luminescence in ZnO A: free exciton transitions (to A valence band) 0 I 0 I 3: (D,X A ) different donor bound excitons 0 I I : (A,X A) different acceptor bound excitons 5 Use PLE to detect excited states of the I acceptor bound exciton... 6a 11 [Gutowski & Hofmann]
21 3. Exciton spectra Complex spectra WET- Recombination luminescence in ZnO A: free exciton transitions (to A valence band) 0 I 0 I 3: (D,X A ) different donor bound excitons 0 I I : (A,X A) different acceptor bound excitons 5 Use PLE to detect excited states of the I acceptor bound exciton... 6a 11 PLE on I 6a in ZnO I 6a I 6a : (A,X A) higher vibronic/rotational states I 6aB I 6aB: (A,X B) ground state (fourfold degenerated) (energy difference A B 5 mev) a e 0 I 6a I 6a : (A,X )* higher excited states A [Gutowski & Hofmann]
22 Applications to materials science Strain induced by heteroepitaxy bandgap changes (similar to temperature dependence): compressive strain bandgap increases valence band crossing (under tensile strain, light holes go up, heavy holes go down) 3. Exciton spectra WET- 1.8 K tensile strain in GaN unstrained compressive strain [Teisseire]
23 Applications to materials science Strain induced by heteroepitaxy 3. Exciton spectra WET- Position depends on strain.* High linewidth depends on strain fields (lattice plane bending, variations in composition) low exciton lifetime (defects, low structural quality) * may also be influenced by charge carrier density (polaron approach) tensile strain in GaN unstrained compressive strain 1.8 K [Teisseire]
24 Applications to materials science Strain induced by heteroepitaxy bandgap changes (similar to temperature dependence): compressive strain bandgap increases valence band crossing (under tensile strain, light holes go up, heavy holes go down) 3. Exciton spectra WET- 1.8 K tensile strain in GaN unstrained compressive strain [Teisseire]
25 Applications to materials science Strain induced by heteroepitaxy PLE reveals higher state donor bound excitons 3. Exciton spectra WET- tensile strain in GaN unstrained compressive strain energy difference between ground and n-th excited state of the (D, X) 0
26 Applications to materials science Strain induced by heteroepitaxy PLE reveals higher state donor bound excitons 3. Exciton spectra WET- tensile strain in GaN unstrained compressive strain (D,X )* 0 B (D,X )* 0 A energy difference between ground and n-th excited state of the (D, X) 0 Result: Valence band crossing in GaN at ev
27 Applications to materials science Evaluating crystalline quality 3. Exciton spectra WET- AlN, 10 K [Prinz07] AlN epilayer on SiC [Taniyasu] AlN bulk crystals [WET] [Feneberg, priv. comm.]
28 Summary Excitons are particles forming the emission ground state in electron hole recombination Frenkel excitons in alkali halides and molecular crystals Wannier-Mott free and impurity bound excitons in semiconductors Exciton detection by optical absorption and radiative luminescence zoo of recombination lines Use in materials science evaluate structural quality and defects (exciton lifetime) evaluate strain state and strain field (position shift) evaluate homogeneity (luminescence maps) 4. Summary WET-
Luminescence basics. Slide # 1
Luminescence basics Types of luminescence Cathodoluminescence: Luminescence due to recombination of EHPs created by energetic electrons. Example: CL mapping system Photoluminescence: Luminescence due to
Luminescence Process
Luminescence Process The absorption and the emission are related to each other and they are described by two terms which are complex conjugate of each other in the interaction Hamiltonian (H er ). In an
Minimal Update of Solid State Physics
Minimal Update of Solid State Physics It is expected that participants are acquainted with basics of solid state physics. Therefore here we will refresh only those aspects, which are absolutely necessary
Lecture contents. Burstein shift Excitons Interband transitions in quantum wells Quantum confined Stark effect. NNSE 618 Lecture #15
1 Lecture contents Burstein shift Excitons Interband transitions in quantum wells Quantum confined Stark effect Absorption edges in semiconductors Offset corresponds to bandgap Abs. coefficient is orders
Direct and Indirect Semiconductor
Direct and Indirect Semiconductor Allowed values of energy can be plotted vs. the propagation constant, k. Since the periodicity of most lattices is different in various direction, the E-k diagram must
Crystal Properties. MS415 Lec. 2. High performance, high current. ZnO. GaN
Crystal Properties Crystal Lattices: Periodic arrangement of atoms Repeated unit cells (solid-state) Stuffing atoms into unit cells Determine mechanical & electrical properties High performance, high current
Review of Optical Properties of Materials
Review of Optical Properties of Materials Review of optics Absorption in semiconductors: qualitative discussion Derivation of Optical Absorption Coefficient in Direct Semiconductors Photons When dealing
Spectroscopy of. Semiconductors. Luminescence OXFORD IVAN PELANT. Academy ofsciences of the Czech Republic, Prague JAN VALENTA
Luminescence Spectroscopy of Semiconductors IVAN PELANT Institute ofphysics, v.v.i. Academy ofsciences of the Czech Republic, Prague JAN VALENTA Department of Chemical Physics and Optics Charles University,
Lecture 8 Interband Transitions. Excitons
Lecture 8 Interband Transitions Excitons Read: FS 4 Purdue University Spring 2016 Prof. Yong P. Chen (yongchen@purdue.edu) Lecture 8 (2/4/2016) Slide 1 Textbook 1: M. Fox Optical Properties of Solids (2
doi: /PhysRevLett
doi: 10.1103/PhysRevLett.77.494 Luminescence Hole Burning and Quantum Size Effect of Charged Excitons in CuCl Quantum Dots Tadashi Kawazoe and Yasuaki Masumoto Institute of Physics and Center for TARA
M R S Internet Journal of Nitride Semiconductor Research
M R S Internet Journal of Nitride Semiconductor Research Volume 2, Article 25 Properties of the Biexciton and the Electron-Hole-Plasma in Highly Excited GaN J.-Chr. Holst, L. Eckey, A. Hoffmann, I. Broser
Optical Properties of Lattice Vibrations
Optical Properties of Lattice Vibrations For a collection of classical charged Simple Harmonic Oscillators, the dielectric function is given by: Where N i is the number of oscillators with frequency ω
Optical Characterization of Solids
D. Dragoman M. Dragoman Optical Characterization of Solids With 184 Figures Springer 1. Elementary Excitations in Solids 1 1.1 Energy Band Structure in Crystalline Materials 2 1.2 k p Method 11 1.3 Numerical
Electronic and Optoelectronic Properties of Semiconductor Structures
Electronic and Optoelectronic Properties of Semiconductor Structures Jasprit Singh University of Michigan, Ann Arbor CAMBRIDGE UNIVERSITY PRESS CONTENTS PREFACE INTRODUCTION xiii xiv 1.1 SURVEY OF ADVANCES
Optical Properties of Semiconductors. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India
Optical Properties of Semiconductors 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/semi2013 Light Matter Interaction Response to external electric
Optical Properties of Solid from DFT
Optical Properties of Solid from DFT 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India & Center for Materials Science and Nanotechnology, University of Oslo, Norway http://folk.uio.no/ravi/cmt15
Fermi polaron-polaritons in MoSe 2
Fermi polaron-polaritons in MoSe 2 Meinrad Sidler, Patrick Back, Ovidiu Cotlet, Ajit Srivastava, Thomas Fink, Martin Kroner, Eugene Demler, Atac Imamoglu Quantum impurity problem Nonperturbative interaction
Carrier Recombination
Notes for ECE-606: Spring 013 Carrier Recombination Professor Mark Lundstrom Electrical and Computer Engineering Purdue University, West Lafayette, IN USA lundstro@purdue.edu /19/13 1 carrier recombination-generation
Note that it is traditional to draw the diagram for semiconductors rotated 90 degrees, i.e. the version on the right above.
5 Semiconductors The nearly free electron model applies equally in the case where the Fermi level lies within a small band gap (semiconductors), as it does when the Fermi level lies within a band (metal)
Density of states for electrons and holes. Distribution function. Conduction and valence bands
Intrinsic Semiconductors In the field of semiconductors electrons and holes are usually referred to as free carriers, or simply carriers, because it is these particles which are responsible for carrying
Three Most Important Topics (MIT) Today
Three Most Important Topics (MIT) Today Electrons in periodic potential Energy gap nearly free electron Bloch Theorem Energy gap tight binding Chapter 1 1 Electrons in Periodic Potential We now know the
Optical Investigation of the Localization Effect in the Quantum Well Structures
Department of Physics Shahrood University of Technology Optical Investigation of the Localization Effect in the Quantum Well Structures Hamid Haratizadeh hamid.haratizadeh@gmail.com IPM, SCHOOL OF PHYSICS,
Metals: the Drude and Sommerfeld models p. 1 Introduction p. 1 What do we know about metals? p. 1 The Drude model p. 2 Assumptions p.
Metals: the Drude and Sommerfeld models p. 1 Introduction p. 1 What do we know about metals? p. 1 The Drude model p. 2 Assumptions p. 2 The relaxation-time approximation p. 3 The failure of the Drude model
TRANSIENT PHOTOLUMINESCENCE SPECTROSCOPY OF GaAs, ZnSe. AND GaAs/GaAlAs QUANTUM WELLS. Sylvain Charbonneau
TRANSIENT PHOTOLUMINESCENCE SPECTROSCOPY OF GaAs, ZnSe AND GaAs/GaAlAs QUANTUM WELLS Sylvain Charbonneau B.Sc., University of Ottawa, 1983 M.Sc., University of Ottawa, 1985 THESIS SUBMITTED IN PARTIAL
Chapter 12: Semiconductors
Chapter 12: Semiconductors Bardeen & Shottky January 30, 2017 Contents 1 Band Structure 4 2 Charge Carrier Density in Intrinsic Semiconductors. 6 3 Doping of Semiconductors 12 4 Carrier Densities in Doped
ESE 372 / Spring 2013 / Lecture 5 Metal Oxide Semiconductor Field Effect Transistor
Metal Oxide Semiconductor Field Effect Transistor V G V G 1 Metal Oxide Semiconductor Field Effect Transistor We will need to understand how this current flows through Si What is electric current? 2 Back
Temperature Dependent Optical Band Gap Measurements of III-V films by Low Temperature Photoluminescence Spectroscopy
Temperature Dependent Optical Band Gap Measurements of III-V films by Low Temperature Photoluminescence Spectroscopy Linda M. Casson, Francis Ndi and Eric Teboul HORIBA Scientific, 3880 Park Avenue, Edison,
Optics and Quantum Optics with Semiconductor Nanostructures. Overview
Optics and Quantum Optics with Semiconductor Nanostructures Stephan W. Koch Department of Physics, Philipps University, Marburg/Germany and Optical Sciences Center, University of Arizona, Tucson/AZ Overview
Chapter 1 Overview of Semiconductor Materials and Physics
Chapter 1 Overview of Semiconductor Materials and Physics Professor Paul K. Chu Conductivity / Resistivity of Insulators, Semiconductors, and Conductors Semiconductor Elements Period II III IV V VI 2 B
Basic cell design. Si cell
Basic cell design Si cell 1 Concepts needed to describe photovoltaic device 1. energy bands in semiconductors: from bonds to bands 2. free carriers: holes and electrons, doping 3. electron and hole current:
Summary lecture VI. with the reduced mass and the dielectric background constant
Summary lecture VI Excitonic binding energy reads with the reduced mass and the dielectric background constant Δ Statistical operator (density matrix) characterizes quantum systems in a mixed state and
Ch. 2: Energy Bands And Charge Carriers In Semiconductors
Ch. 2: Energy Bands And Charge Carriers In Semiconductors Discrete energy levels arise from balance of attraction force between electrons and nucleus and repulsion force between electrons each electron
Luminescence of excitons
Luminescence of excitons 7 In an ideal pure semiconductor, the primary electronic excitation is a free electron hole pair, the energy required for its creation (supplied, for example, by an incident photon)
PHYSICS OF SEMICONDUCTORS AND THEIR HETEROSTRUCTURES
PHYSICS OF SEMICONDUCTORS AND THEIR HETEROSTRUCTURES Jasprit Singh University of Michigan McGraw-Hill, Inc. New York St. Louis San Francisco Auckland Bogota Caracas Lisbon London Madrid Mexico Milan Montreal
EECS143 Microfabrication Technology
EECS143 Microfabrication Technology Professor Ali Javey Introduction to Materials Lecture 1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) Why Semiconductors? Conductors e.g
In this block the two transport mechanisms will be discussed: diffusion and drift.
ET3034TUx - 2.3.3 Transport of charge carriers What are the charge carrier transport principles? In this block the two transport mechanisms will be discussed: diffusion and drift. We will discuss that
Optical spectroscopy of carrier dynamics in semiconductor nanostructures de Jong, E.M.L.D.
UvA-DARE (Digital Academic Repository) Optical spectroscopy of carrier dynamics in semiconductor nanostructures de Jong, E.M.L.D. Link to publication Citation for published version (APA): de Jong, EM-LD.
The Semiconductor in Equilibrium
Lecture 6 Semiconductor physics IV The Semiconductor in Equilibrium Equilibrium, or thermal equilibrium No external forces such as voltages, electric fields. Magnetic fields, or temperature gradients are
OPTICAL PROPERTIES of Nanomaterials
OPTICAL PROPERTIES of Nanomaterials Advanced Reading Optical Properties and Spectroscopy of Nanomaterials Jin Zhong Zhang World Scientific, Singapore, 2009. Optical Properties Many of the optical properties
Supplementary Materials
Supplementary Materials Sample characterization The presence of Si-QDs is established by Transmission Electron Microscopy (TEM), by which the average QD diameter of d QD 2.2 ± 0.5 nm has been determined
Basic Semiconductor Physics
Chihiro Hamaguchi Basic Semiconductor Physics With 177 Figures and 25 Tables Springer 1. Energy Band Structures of Semiconductors 1 1.1 Free-Electron Model 1 1.2 Bloch Theorem 3 1.3 Nearly Free Electron
ET3034TUx Utilization of band gap energy
ET3034TUx - 3.3.1 - Utilization of band gap energy In the last two weeks we have discussed the working principle of a solar cell and the external parameters that define the performance of a solar cell.
1 Review of semiconductor materials and physics
Part One Devices 1 Review of semiconductor materials and physics 1.1 Executive summary Semiconductor devices are fabricated using specific materials that offer the desired physical properties. There are
Lecture 3b. Bonding Model and Dopants. Reading: (Cont d) Notes and Anderson 2 sections
Lecture 3b Bonding Model and Dopants Reading: (Cont d) Notes and Anderson 2 sections 2.3-2.7 The need for more control over carrier concentration Without help the total number of carriers (electrons and
Chapter 2 Optical Transitions
Chapter 2 Optical Transitions 2.1 Introduction Among energy states, the state with the lowest energy is most stable. Therefore, the electrons in semiconductors tend to stay in low energy states. If they
EE143 Fall 2016 Microfabrication Technologies. Evolution of Devices
EE143 Fall 2016 Microfabrication Technologies Prof. Ming C. Wu wu@eecs.berkeley.edu 511 Sutardja Dai Hall (SDH) 1-1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) 1-2 1 Why
Electron Dynamiχ MPRG Fritz-Haber-Institut der Max-Planck-Gesellschaft
Electron Dynamiχ MPRG Fritz-Haber-Institut der Max-Planck-Gesellschaft How exciting! 2016 Berlin, 3-6 August laura.foglia@elettra.eu 1 Current research challenges V Light Harvesting Light Emission Energy
Three-Dimensional Silicon-Germanium Nanostructures for Light Emitters and On-Chip Optical. Interconnects
Three-Dimensional Silicon-Germanium Nanostructures for Light Emitters and On-Chip Optical eptember 2011 Interconnects Leonid Tsybeskov Department of Electrical and Computer Engineering New Jersey Institute
interband transitions in semiconductors M. Fox, Optical Properties of Solids, Oxford Master Series in Condensed Matter Physics
interband transitions in semiconductors M. Fox, Optical Properties of Solids, Oxford Master Series in Condensed Matter Physics interband transitions in quantum wells Atomic wavefunction of carriers in
Chapter 3 Properties of Nanostructures
Chapter 3 Properties of Nanostructures In Chapter 2, the reduction of the extent of a solid in one or more dimensions was shown to lead to a dramatic alteration of the overall behavior of the solids. Generally,
Semiconductor Physics and Devices Chapter 3.
Introduction to the Quantum Theory of Solids We applied quantum mechanics and Schrödinger s equation to determine the behavior of electrons in a potential. Important findings Semiconductor Physics and
Spin Dynamics in Single GaAs Nanowires
1 Dr. Max Mustermann Referat Kommunikation & Marketing Verwaltung Spin Dynamics in Single GaAs Nanowires F. Dirnberger, S. Furthmeier, M. Forsch, A. Bayer, J. Hubmann, B. Bauer, J. Zweck, E. Reiger, C.
Electron Energy, E E = 0. Free electron. 3s Band 2p Band Overlapping energy bands. 3p 3s 2p 2s. 2s Band. Electrons. 1s ATOM SOLID.
Electron Energy, E Free electron Vacuum level 3p 3s 2p 2s 2s Band 3s Band 2p Band Overlapping energy bands Electrons E = 0 1s ATOM 1s SOLID In a metal the various energy bands overlap to give a single
Resonantly Excited Time-Resolved Photoluminescence Study of Self-Organized InGaAs/GaAs Quantum Dots
R. Heitz et al.: PL Study of Self-Organized InGaAs/GaAs Quantum Dots 65 phys. stat. sol. b) 221, 65 2000) Subject classification: 73.61.Ey; 78.47.+p; 78.55.Cr; 78.66.Fd; S7.12 Resonantly Excited Time-Resolved
Physics of Semiconductors (Problems for report)
Physics of Semiconductors (Problems for report) Shingo Katsumoto Institute for Solid State Physics, University of Tokyo July, 0 Choose two from the following eight problems and solve them. I. Fundamentals
Electron spins in nonmagnetic semiconductors
Electron spins in nonmagnetic semiconductors Yuichiro K. Kato Institute of Engineering Innovation, The University of Tokyo Physics of non-interacting spins Optical spin injection and detection Spin manipulation
Quantum Mechanical Modelling and Optical Spectroscopy of Zn(Mg,Cd)O Heterostructures
UNIVERSITY OF OSLO DEPARTMENT OF PHYSICS MASTER S THESIS Quantum Mechanical Modelling and Optical Spectroscopy of Zn(Mg,Cd)O Heterostructures Marius Mordal Bakke A thesis submitted in partial fulfilment
Vibronic Coupling in Quantum Wires: Applications to Polydiacetylene
Vibronic Coupling in Quantum Wires: Applications to Polydiacetylene An Exhaustively Researched Report by Will Bassett and Cole Johnson Overall Goal In order to elucidate the absorbance spectra of different
Fluorescence Spectroscopy
Fluorescence Spectroscopy Frequency and time dependent emission Emission and Excitation fluorescence spectra Stokes Shift: influence of molecular vibrations and solvent Time resolved fluorescence measurements
Lecture 3: Optical Properties of Insulators, Semiconductors, and Metals. 5 nm
Metals Lecture 3: Optical Properties of Insulators, Semiconductors, and Metals 5 nm Course Info Next Week (Sept. 5 and 7) no classes First H/W is due Sept. 1 The Previous Lecture Origin frequency dependence
X-Ray Photoelectron Spectroscopy (XPS)-2
X-Ray Photoelectron Spectroscopy (XPS)-2 Louis Scudiero http://www.wsu.edu/~pchemlab ; 5-2669 Fulmer 261A Electron Spectroscopy for Chemical Analysis (ESCA) The 3 step model: 1.Optical excitation 2.Transport
QUANTUM WELLS, WIRES AND DOTS
QUANTUM WELLS, WIRES AND DOTS Theoretical and Computational Physics of Semiconductor Nanostructures Second Edition Paul Harrison The University of Leeds, UK /Cf}\WILEY~ ^INTERSCIENCE JOHN WILEY & SONS,
SEMICONDUCTOR PHYSICS
SEMICONDUCTOR PHYSICS by Dibyendu Chowdhury Semiconductors The materials whose electrical conductivity lies between those of conductors and insulators, are known as semiconductors. Silicon Germanium Cadmium
Atoms? All matters on earth made of atoms (made up of elements or combination of elements).
Chapter 1 Atoms? All matters on earth made of atoms (made up of elements or combination of elements). Atomic Structure Atom is the smallest particle of an element that can exist in a stable or independent
TIME-RESOLVED LUMINESCENCE SPECTRA IN COLORLESS ANATASE TiO 2 SINGLE CRYSTAL
TIME-RESOLVED LUMINESCENCE SPECTRA IN COLORLESS ANATASE TiO 2 SINGLE CRYSTAL K. Wakabayashi, Y. Yamaguchi, T. Sekiya, S. Kurita Department of Physics, Faculty of Engineering, Yokohama National University
From Last Time Important new Quantum Mechanical Concepts. Atoms and Molecules. Today. Symmetry. Simple molecules.
Today From Last Time Important new Quantum Mechanical Concepts Indistinguishability: Symmetries of the wavefunction: Symmetric and Antisymmetric Pauli exclusion principle: only one fermion per state Spin
X-Ray Photoelectron Spectroscopy (XPS)-2
X-Ray Photoelectron Spectroscopy (XPS)-2 Louis Scudiero http://www.wsu.edu/~scudiero; 5-2669 Fulmer 261A Electron Spectroscopy for Chemical Analysis (ESCA) The 3 step model: 1.Optical excitation 2.Transport
ECE 606 Homework Week 7 Mark Lundstrom Purdue University (revised 2/25/13) e E i! E T
ECE 606 Homework Week 7 Mark Lundstrom Purdue University (revised 2/25/13) 1) Consider an n- type semiconductor for which the only states in the bandgap are donor levels (i.e. ( E T = E D ). Begin with
Hexagonal boron nitride is an indirect bandgap semiconductor
Hexagonal boron nitride is an indirect bandgap semiconductor G. Cassabois, P. Valvin, B. Gil Laboratoire Charles Coulomb, UMR 5221 CNRS-Université de Montpellier, F-34095, Montpellier, France A. EFFECTIVE
Lecture 8. Equations of State, Equilibrium and Einstein Relationships and Generation/Recombination
Lecture 8 Equations of State, Equilibrium and Einstein Relationships and Generation/Recombination Reading: (Cont d) Notes and Anderson 2 sections 3.4-3.11 Energy Equilibrium Concept Consider a non-uniformly
Intensity / a.u. 2 theta / deg. MAPbI 3. 1:1 MaPbI 3-x. Cl x 3:1. Supplementary figures
Intensity / a.u. Supplementary figures 110 MAPbI 3 1:1 MaPbI 3-x Cl x 3:1 220 330 0 10 15 20 25 30 35 40 45 2 theta / deg Supplementary Fig. 1 X-ray Diffraction (XRD) patterns of MAPbI3 and MAPbI 3-x Cl
Chapter 6 Photoluminescence Spectroscopy
Chapter 6 Photoluminescence Spectroscopy Course Code: SSCP 4473 Course Name: Spectroscopy & Materials Analysis Sib Krishna Ghoshal (PhD) Advanced Optical Materials Research Group Physics Department, Faculty
Light emission from strained germanium
Light emission from strained germanium Supplementary information P. Boucaud, 1, a) M. El Kurdi, 1 S. Sauvage, 1 M. de Kersauson, 1 A. Ghrib, 1 and X. Checoury 1 Institut d Electronique Fondamentale, CNRS
(002)(110) (004)(220) (222) (112) (211) (202) (200) * * 2θ (degree)
Supplementary Figures. (002)(110) Tetragonal I4/mcm Intensity (a.u) (004)(220) 10 (112) (211) (202) 20 Supplementary Figure 1. X-ray diffraction (XRD) pattern of the sample. The XRD characterization indicates
Lecture 18 Luminescence Centers
Lecture 18 Luminescence Centers Read: FS9 (Al2O3 sapphire with different colors) Purdue University Spring 2016 Prof. Yong P. Chen (yongchen@purdue.edu) Lecture 18 (3/24/2016) Slide 1 Basic physics: Vibronic
Engineering 2000 Chapter 8 Semiconductors. ENG2000: R.I. Hornsey Semi: 1
Engineering 2000 Chapter 8 Semiconductors ENG2000: R.I. Hornsey Semi: 1 Overview We need to know the electrical properties of Si To do this, we must also draw on some of the physical properties and we
Enhancement of Ionization Efficiency of Acceptors by Their Excited States in Heavily Doped p-type GaN and Wide Bandgap Semiconductors
Enhancement of Ionization Efficiency of cceptors by Their Excited States in Heavily Doped p-type GaN and Wide Bandgap Semiconductors Hideharu Matsuura Osaka Electro-Communication University 2004 Joint
Structural and Optical Properties of III-III-V-N Type
i Structural and Optical Properties of III-III-V-N Type Alloy Films and Their Quantum Wells ( III-III-V- N 型混晶薄膜および量子井戸の構造的および光学的性質 ) This dissertation is submitted as a partial fulfillment of the requirements
EE 346: Semiconductor Devices
EE 346: Semiconductor Devices Lecture - 5 02/01/2017 Tewodros A. Zewde 1 The One-Electron Atom The potential function is due to the coulomb attraction between the proton and electron and is given by where
PH575 Spring Lecture #19 Semiconductors: electrical & optical properties: Kittel Ch. 8 pp ; Ch. 20
PH575 Spring 2014 Lecture #19 Semiconductors: electrical & optical properties: Kittel Ch. 8 pp. 205-214; Ch. 20 Simplified diagram of the filling of electronic band structure in various types of material,
Chemistry Instrumental Analysis Lecture 8. Chem 4631
Chemistry 4631 Instrumental Analysis Lecture 8 UV to IR Components of Optical Basic components of spectroscopic instruments: stable source of radiant energy transparent container to hold sample device
Recombination Dynamics in Zinc Oxide. Luigi Santamaria Amato Ph.D. Candidate (XXIII cycle)
Recombination Dynamics in Zinc Oxide Luigi Santamaria Amato Ph.D. Candidate (XXIII cycle) Tutors: Prof. P. Maddalena Dr. S. Lettieri Referees: Prof. L. Marrucci Prof. D. Ninno 1 Introduction Chapter 1
2 Fundamentals of Flash Lamp Annealing of Shallow Boron-Doped Silicon
2 Fundamentals of Flash Lamp Annealing of Shallow Boron-Doped Silicon MSA of semiconductors is usually performed using flash lamps. It has been shown that FLA holds the balance between effective dopant
smal band gap Saturday, April 9, 2011
small band gap upper (conduction) band empty small gap valence band filled 2s 2p 2s 2p hybrid (s+p)band 2p no gap 2s (depend on the crystallographic orientation) extrinsic semiconductor semi-metal electron
Session 5: Solid State Physics. Charge Mobility Drift Diffusion Recombination-Generation
Session 5: Solid State Physics Charge Mobility Drift Diffusion Recombination-Generation 1 Outline A B C D E F G H I J 2 Mobile Charge Carriers in Semiconductors Three primary types of carrier action occur
Supplementary Figure 1 Comparison of single quantum emitters on two type of substrates:
Supplementary Figure 1 Comparison of single quantum emitters on two type of substrates: a, Photoluminescence (PL) spectrum of localized excitons in a WSe 2 monolayer, exfoliated onto a SiO 2 /Si substrate
Supplementary Figure 1 Interlayer exciton PL peak position and heterostructure twisting angle. a, Photoluminescence from the interlayer exciton for
Supplementary Figure 1 Interlayer exciton PL peak position and heterostructure twisting angle. a, Photoluminescence from the interlayer exciton for six WSe 2 -MoSe 2 heterostructures under cw laser excitation
Chapter 6: Light-Emitting Diodes
Chapter 6: Light-Emitting Diodes Photoluminescence and electroluminescence Basic transitions Luminescence efficiency Light-emitting diodes Internal quantum efficiency External quantum efficiency Device
ENERGY BANDS AND GAPS IN SEMICONDUCTOR. Muhammad Hafeez Javed
ENERGY BANDS AND GAPS IN SEMICONDUCTOR Muhammad Hafeez Javed www.rmhjaved.com rmhjaved@gmail.com Out Line Introduction Energy band Classification of materials Direct and indirect band gap of SC Classification
Lecture 18: Semiconductors - continued (Kittel Ch. 8)
Lecture 18: Semiconductors - continued (Kittel Ch. 8) + a - Donors and acceptors J U,e e J q,e Transport of charge and energy h E J q,e J U,h Physics 460 F 2006 Lect 18 1 Outline More on concentrations
Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN Alloys
Vol. 113 (2008) ACTA PHYSICA POLONICA A No. 3 Proceedings of the 13th International Symposium UFPS, Vilnius, Lithuania 2007 Investigation of Optical Nonlinearities and Carrier Dynamics in In-Rich InGaN
ATOMIC STRUCTURE, ELECTRONS, AND PERIODICITY
ATOMIC STRUCTURE, ELECTRONS, AND PERIODICITY All matter is made of atoms. There are a limited number of types of atoms; these are the elements. (EU 1.A) Development of Atomic Theory Atoms are so small
PH575 Spring Lecture #20 Semiconductors: optical properties: Kittel Ch. 8 pp ; Ch 15 pp
PH575 Spring 2014 Lecture #20 Semiconductors: optical properties: Kittel Ch. 8 pp. 187-191; Ch 15 pp. 435-444 Figure VI-1-1: Different types of optical absorption phenomena; (1) transitions of highlying
nano.tul.cz Inovace a rozvoj studia nanomateriálů na TUL
Inovace a rozvoj studia nanomateriálů na TUL nano.tul.cz Tyto materiály byly vytvořeny v rámci projektu ESF OP VK: Inovace a rozvoj studia nanomateriálů na Technické univerzitě v Liberci Units for the
Microscopic Modelling of the Optical Properties of Quantum-Well Semiconductor Lasers
Microscopic Modelling of the Optical Properties of Quantum-Well Semiconductor Lasers Stephan W. Koch Department of Physics Philipps University, Marburg/Germany OVERVIEW - Outline of Theory - Gain/Absorption
Calculating Band Structure
Calculating Band Structure Nearly free electron Assume plane wave solution for electrons Weak potential V(x) Brillouin zone edge Tight binding method Electrons in local atomic states (bound states) Interatomic
Semiconductor physics I. The Crystal Structure of Solids
Lecture 3 Semiconductor physics I The Crystal Structure of Solids 1 Semiconductor materials Types of solids Space lattices Atomic Bonding Imperfection and doping in SOLIDS 2 Semiconductor Semiconductors
University of Groningen. Photophysics of nanomaterials for opto-electronic applications Kahmann, Simon
University of Groningen Photophysics of nanomaterials for opto-electronic applications Kahmann, Simon IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to
Supporting Information
Electronic Supplementary Material (ESI) for Nanoscale. This journal is The Royal Society of Chemistry 2015 Supporting Information Single Layer Lead Iodide: Computational Exploration of Structural, Electronic
Energy Band Calculations for Dynamic Gain Models in Semiconductor Quantum Well Lasers
Energy Band Calculations for Dynamic Gain Models in School of Electrical and Electronic Engineering University of Nottingham; Nottingham NG7 2RD; UK Email: eexpjb1@nottingham.ac.uk Presentation Outline