Optical Properties of Materials and Their Applications

Edited by Jai Singh, AM, PhD, College of Engineering, IT and Environment, Charles Darwin University, Darwin, Australia. Series Editors Arthur Willoughby University of Southampton, Southampton, UK Peter Capper formerly of Ex-Leonardo M. W. Ltd, Southampton, UK Safa Kasap University of Saskatchewan, Saskatoon, Canada

• List of Contributors xvSeries Preface xviiPreface xix1 Fundamental Optical Properties of Materials I 1S.O. Kasap, W.C. Tan, Jai Singh, and Asim K. Ray1.1 Introduction 11.2 Optical Constants n and K 21.2.1 Refractive Index and Extinction Coefficient 21.2.2 n and K, and Kramers–Kronig Relations 51.3 Refractive Index and Dispersion 71.3.1 Cauchy Dispersion Relation 71.3.2 Sellmeier Equation 81.3.3 Refractive Index of Semiconductors 101.3.3.1 Refractive Index of Crystalline Semiconductors 101.3.3.2 Bandgap and Temperature Dependence 111.3.4 Refractive Index of Glasses 111.3.5 Wemple–DiDomenico Dispersion Relation 141.3.6 Group Index 151.4 The Swanepoel Technique: Measurement of n and 𝛼 for Thin Films on Substrates 161.4.1 Uniform Thickness Films 161.4.2 Thin Films with Non-uniform Thickness 221.5 Transmittance and Reflectance of a Partially Transparent Plate 251.6 Optical Properties and Diffuse Reflection: Schuster–Kubelka–Munk Theory 271.7 Conclusions 31Acknowledgments 31References 322 Fundamental Optical Properties of Materials II 37S.O. Kasap, K. Koughia, Jai Singh, Harry E. Ruda, and Asim K. Ray2.1 Introduction 372.2 Lattice or Reststrahlen Absorption and Infrared Reflection 402.3 Free Carrier Absorption (FCA) 422.4 Band-to-Band or Fundamental Absorption (Crystalline Solids) 452.5 Impurity Absorption and Rare-Earth Ions 482.6 Effect of External Fields 542.6.1 Electro-Optic Effects 542.6.2 Electro-Absorption and Franz–Keldysh Effect 552.6.3 Faraday Effect 562.7 Effective Medium Approximations 582.8 Conclusions 61Acknowledgments 61References 623 Optical Properties of Disordered Condensed Matter 67Koichi Shimakawa, Jai Singh, and S.K. O’Leary3.1 Introduction 673.2 Fundamental Optical Absorption (Experimental) 693.2.1 Amorphous Chalcogenides 693.2.2 Hydrogenated Nano-Crystalline Silicon (nc-Si:H) 723.3 Absorption Coefficient (Theory) 743.4 Compositional Variation of the Optical Bandgap 793.4.1 In Amorphous Chalcogenides 793.5 Conclusions 80References 804 Optical Properties of Glasses 83Andrew Edgar4.1 Introduction 834.2 The Refractive Index 844.3 Glass Interfaces 864.4 Dispersion 884.5 Sensitivity of the Refractive Index 904.5.1 Temperature Dependence 904.5.2 Stress Dependence 914.5.3 Magnetic Field Dependence—The Faraday Effect 924.5.4 Chemical Perturbations—Molar Refractivity 944.6 Glass Color 954.6.1 Coloration by Colloidal Metals and Semiconductors 954.6.2 Optical Absorption in Rare-Earth-Doped Glass 964.6.3 Absorption by 3d Metal Ions 994.7 Fluorescence in Rare-Earth-Doped Glass 1024.8 Glasses for Fiber Optics 1044.9 Refractive Index Engineering 1064.10 Glass and Glass–Fiber Lasers and Amplifiers 1094.11 Valence Change Glasses 1114.12 Transparent Glass Ceramics 1144.12.1 Introduction 1144.12.2 Theoretical Basis for Transparency 1164.12.3 Rare-Earth-Doped Transparent Glass Ceramics for Active Photonics 1204.12.4 Ferroelectric Transparent Glass Ceramics 1214.12.5 Transparent Glass Ceramics for X-ray Storage Phosphors 1214.13 Conclusions 124References 1245 Concept of Excitons 129Jai Singh, Harry E. Ruda, M.R. Narayan, and D. Ompong5.1 Introduction 1295.2 Excitons in Crystalline Solids 1305.2.1 Excitonic Absorption in Crystalline Solids 1335.3 Excitons in Amorphous Semiconductors 1355.3.1 Excitonic Absorption in Amorphous Solids 1375.4 Excitons in Organic Semiconductors 1395.4.1 Photoexcitation and Formation of Excitons 1405.4.1.1 Photoexcitation of Singlet Excitons Due to Exciton–Photon Interaction 1415.4.1.2 Excitation of Triplet Excitons 1425.4.2 Exciton Up-Conversion 1475.4.3 Exciton Dissociation 1485.4.3.1 Conversion from Frenkel to CT Excitons 1515.4.3.2 Dissociation of CT Excitons 1525.5 Conclusions 153References 1546 Photoluminescence 157Takeshi Aoki6.1 Introduction 1576.2 Fundamental Aspects of Photoluminescence (PL) in Materials 1586.2.1 Intrinsic Photoluminescence 1596.2.2 Extrinsic Photoluminescence 1606.2.3 Up-Conversion Photoluminescence (UCPL) 1626.2.4 Other Related Optical Transitions 1636.3 Experimental Aspects 1646.3.1 Static PL Spectroscopy 1646.3.2 Photoluminescence Excitation Spectroscopy (PLE) and Photoluminescence Absorption Spectroscopy (PLAS) 1676.3.3 Time Resolved Spectroscopy (TRS) 1686.3.4 Time-Correlated Single Photon Counting (TCSPC) 1716.3.5 Frequency-Resolved Spectroscopy (FRS) 1726.3.6 Quadrature Frequency Resolved Spectroscopy (QFRS) 1736.4 Photoluminescence Lifetime Spectroscopy of Amorphous Semiconductors by QFRS Technique 1756.4.1 Overview 1756.4.2 Dual-Phase Double Lock-in (DPDL) QFRS Technique 1766.4.3 Exploring Broad PL Lifetime Distribution in a-Si:H by Wideband QFRS 1786.4.3.1 Effects of Excitation Intensity, Excitation, and Emission Energies 1796.4.3.2 Temperature Dependence 1846.4.3.3 Effect of Electric and Magnetic Fields 1856.4.4 Residual PL Decay of a-Si:H 1896.5 QFRS on Up-Conversion Photoluminescence (UCPL) of RE-Doped Materials 1926.6 Conclusions 197Acknowledgments 198References 1987 Photoluminescence, Photoinduced Changes, and Electroluminescence in Noncrystalline Semiconductors 203Jai Singh7.1 Introduction 2037.2 Photoluminescence 2057.2.1 Radiative Recombination Operator and Transition Matrix Element 2067.2.2 Rates of Spontaneous Emission 2117.2.2.1 At Nonthermal Equilibrium 2127.2.2.2 At Thermal Equilibrium 2147.2.2.3 Determining E0 2157.2.3 Results of Spontaneous Emission and Radiative Lifetime 2167.2.4 Temperature Dependence of PL 2227.2.5 Excitonic Concept 2237.3 Photoinduced Changes in Amorphous Chalcogenides 2257.3.1 Effect of Photo-Excitation and Phonon Interaction 2267.3.2 Excitation of a Single Electron–Hole Pair 2287.3.3 Pairing of Like Excited Charge Carriers 2297.4 Radiative Recombination of Excitons in Organic Semiconductors 2327.4.1 Rate of Fluorescence 2337.4.2 Rate of Phosphorescence 2337.4.3 Organic Light Emitting Diodes (OLEDs) 2347.4.3.1 Second- and Third-Generation OLEDs: TADF 2357.5 Conclusions 236Acknowledgments 236References 2378 Photoinduced Bond Breaking and Volume Change in Chalcogenide Glasses 241Sandor Kugler, Rozália Lukács, and Koichi Shimakawa8.1 Introduction 2418.2 Atomic-Scale Computer Simulations of Photoinduced Volume Changes 2438.3 Effect of Illumination 2448.4 Kinetics of Volume Change 2458.4.1 a-Se 2458.4.2 a-As2Se3 2468.5 Additional Remarks 2488.6 Conclusions 249References 2499 Properties and Applications of Photonic Crystals 251Harry E. Ruda and Naomi Matsuura9.1 Introduction 2519.2 PC Overview 2529.2.1 Introduction to PCs 2529.2.2 Nanoengineering of PC Architectures 2539.2.3 Materials Selection for PCs 2559.3 Tunable PCs 2559.3.1 Tuning PC Response by Changing the Refractive Index of Constituent Materials 2569.3.1.1 PC Refractive Index Tuning Using Light 2569.3.1.2 PC Refractive Index Tuning Using an Applied Electric Field 2569.3.1.3 Refractive Index Tuning of Infiltrated PCs 2579.3.1.4 PC Refractive Index Tuning by Altering the Concentration of Free Carriers (Using Electric Field or Temperature) in Semiconductor-Based PCs 2579.3.2 Tuning PC Response by Altering the Physical Structure of the PC 2589.3.2.1 Tuning PC Response Using Temperature 2589.3.2.2 Tuning PC Response Using Magnetism 2589.3.2.3 Tuning PC Response Using Strain 2589.3.2.4 Tuning PC Response Using Piezoelectric Effects 2599.3.2.5 Tuning PC Response Using MEMS Actuation 2609.4 Selected Applications of PC 2609.4.1 Waveguide Devices 2619.4.2 Dispersive Devices 2629.4.3 Add/Drop Multiplexing Devices 2629.4.4 Applications of PCs for Light-Emitting Diodes (LEDs) and Lasers 2639.5 Conclusions 265Acknowledgments 265References 26510 Nonlinear Optical Properties of Photonic Glasses 269Keiji Tanaka10.1 Introduction 26910.2 Photonic Glass 27110.3 Nonlinear Absorption and Refractivity 27210.3.1 Fundamentals 27210.3.2 Two-Photon Absorption 27510.3.3 Nonlinear Refractivity 27810.4 Nonlinear Excitation-Induced Structural Changes 28010.4.1 Fundamentals 28010.4.2 Oxides 28110.4.3 Chalcogenides 28310.5 Conclusions 28510.A Addendum: Perspectives on Optical Devices 286References 28811 Optical Properties of Organic Semiconductors 295Takashi Kobayashi and Hiroyoshi Naito11.1 Introduction 29511.2 Molecular Structure of π-Conjugated Polymers 29611.3 Theoretical Models 29811.4 Absorption Spectrum 30011.5 Photoluminescence 30411.6 Non-Emissive Excited States 30611.7 Electron–Electron Interaction 30911.8 Interchain Interaction 31411.9 Conclusions 320References 32112 Organic Semiconductors and Applications 323Furong Zhu12.1 Introduction 32312.1.1 Device Architecture and Operation Principle 32412.1.2 Technical Challenges and Process Integration 32512.2 Anode Modification for Enhanced OLED Performance 32712.2.1 Low-Temperature High-Performance ITO 32712.2.1.1 Experimental Methods 32812.2.1.2 Morphological Properties 32912.2.1.3 Electrical Properties 33112.2.1.4 Optical Properties 33312.2.1.5 Compositional Analysis 33612.2.2 Anode Modification 33912.2.3 Electroluminescence Performance of OLEDs 34012.3 Flexible OLEDs 34512.3.1 Flexible OLEDs on Ultrathin Glass Substrate 34612.3.2 Flexible Top-Emitting OLEDs on Plastic Foils 34712.3.2.1 Top-Emitting OLEDs 34812.3.2.2 Flexible TOLEDs on Plastic Foils 35012.4 Solution-Processable High-Performing OLEDs 35312.4.1 Performance of OLEDs with a Hybrid MoO3-PEDOT:PSS Hole Injection Layer (HIL) 35312.4.2 Morphological Properties of the MoO3-PEDOT:PSS HIL 36112.4.3 Surface Electronic Properties of MoO3-PEDOT:PSS HIL 36312.5 Conclusions 368References 36913 Transparent White OLEDs 373Choi Wing Hong and Furong Zhu13.1 Introduction—Progress in Transparent WOLEDs 37313.2 Performance of WOLEDs 37413.2.1 Optimization of Dichromatic WOLEDs 37413.2.2 J-L-V Characteristics of WOLEDs 37713.2.3 Electron-Hole Current Balance in Transparent WOLEDs 38413.3 Emission Behavior of Transparent WOLEDs 38613.3.1 Visible-Light Transparency of WOLEDs 38613.3.2 L-J Characteristics of Transparent WOLEDs 39013.3.3 Angular-Dependent Color Stability of Transparent WOLEDs 39513.4 Conclusions 400References 40014 Optical Properties of Thin Films 403V.-V. Truong, S. Tanemura, A. Haché, and L. Miao14.1 Introduction 40314.2 Optics of Thin Films 40414.2.1 An Isotropic Film on a Substrate 40414.2.2 Matrix Methods for Multi-Layered Structures 40614.2.3 Anisotropic Films 40714.3 Reflection-Transmission Photoellipsometry for Determination of Optical Constants 40814.3.1 Photoellipsometry of a Thick or a Thin Film 40814.3.2 Photoellipsometry for a Stack of Thick and Thin Films 41014.3.3 Remarks on the Reflection-Transmission Photoellipsometry Method 41214.4 Application of Thin Films to Energy Management and Renewable-Energy Technologies 41214.4.1 Electrochromic Thin Films 41314.4.2 Pure and Metal-Doped VO2 Thermochromic Thin Films 41414.4.3 Temperature-Stabilized V1-xWxO2 Sky Radiator Films 41714.4.4 Optical Functional TiO2 Thin Film for Environmentally Friendly Technologies 42014.5 Application of Tunable Thin Films to Phase and Polarization Modulation 42414.6 Conclusions 430References 43015 Optical Characterization of Materials by Spectroscopic Ellipsometry 435J. Mistrík15.1 Introduction 43515.2 Notions of Light Polarization 43615.3 Measureable Quantities 43815.4 Instrumentation 44115.5 Single Interface 44215.6 Single Layer 44815.7 Multilayer 45415.8 Linear Grating 45815.9 Conclusions 462Acknowledgments 463References 46316 Excitonic Processes in Quantum Wells 465Jai Singh and I.-K. Oh16.1 Introduction 46516.2 Exciton–Phonon Interaction 46616.3 Exciton Formation in QWs Assisted by Phonons 46716.4 Nonradiative Relaxation of Free Excitons 47416.4.1 Intraband Processes 47516.4.2 Interband Processes 47916.5 Quasi-2D Free-Exciton Linewidth 48516.6 Localization of Free Excitons 49116.7 Conclusions 499References 50017 Optoelectronic Properties and Applications of Quantum Dots 503Jørn M. Hvam17.1 Introduction 50317.2 Epitaxial Growth and Structure of Quantum Dots 50417.2.1 Self-Assembled Quantum Dots 50417.2.2 Site-Controlled Growth on Patterned Substrates 50517.2.3 Natural or Interface Quantum Dots 50617.2.4 Quantum Dots in Nanowires 50717.3 Excitons in Quantum Dots 50817.3.1 Quantum-Dot Bandgap 50917.3.2 Optical Transitions 51017.4 Optical Properties 51317.4.1 Radiative Lifetime, Oscillator Strength, and Internal Quantum Efficiency 51417.4.2 Linewidth, Coherence, and Dephasing 51617.4.3 Transient Four-Wave Mixing 51717.5 Quantum Dot Applications 52017.5.1 Quantum Dot Lasers and Optical Amplifiers 52017.5.1.1 Gain Dynamics 52217.5.1.2 Homogeneous Broadening and Dephasing 52417.5.1.3 Long-Wavelength Lasers 52617.5.1.4 Nano Lasers 52717.5.2 Single-Photon Emitters 52717.5.2.1 Micropillars and Nanowires 53017.5.2.2 Photonic Crystal Waveguide 53117.6 Conclusions 533Acknowledgments 534References 53418 Perovskites – Revisiting the Venerable ABX3 Family with Organic Flexibility and New Applications 537Junwei Xu, D.L. Carroll, K. Biswas, F. Moretti, S. Gridin, and R.T.Williams18.1 Introduction 53718.1.1 Review 53718.1.2 The Structures 53818.1.2.1 Simple Cubic Frameworks 53818.1.2.2 The Multiplicity of Hybrids 53918.1.2.3 Structural Variation 54018.2 Hybrid Perovskites in Photovoltaics 54418.2.1 Review 54418.2.2 The Phenomena Characterized as “Defect Tolerance” 54818.3 Light-Emitting Diodes Using Solution-Processed Lead Halide Perovskites 54918.3.1 Review 54918.3.2 Construction and Characterization of LEDs Utilizing CsPbBr3 Nano-Inclusions in Cs4PbBr6 as the Electroluminescent Medium 55318.4 Ionizing Radiation Detectors Using Lead Halide Perovskite Materials: Basics, Progress, and Prospects 56218.5 Conclusions 582Acknowledgments 583References 58319 Optical Properties and Spin Dynamics of Diluted Magnetic Semiconductor Nanostructures 589Akihiro Murayama and Yasuo Oka19.1 Introduction 58919.2 Quantum Wells 59119.2.1 Spin Injection 59119.2.2 Study of Spin Dynamics by Pump-Probe Spectroscopy 59419.3 Fabrication of Nanostructures by Electron-Beam Lithography 59619.4 Self-Assembled Quantum Dots 59919.5 Hybrid Nanostructures with Ferromagnetic Materials 60419.6 Conclusions 607Acknowledgments 608References 60920 Kinetics of the Persistent Photoconductivity in Crystalline III-V Semiconductors 611Ruben Jeronimo Freitas and Koichi Shimakawa20.1 Introduction 61120.2 A Review of PPC in III-V Semiconductors 61320.3 Key Physical Terms Related to PPC 61520.3.1 Dispersive Reaction 61520.3.2 SEF and Power Law 61620.3.3 Waiting Time Distribution 61720.4 Kinetics of PPC in III-V Semiconductors 61720.5 Conclusions 623Acknowledgments 62320.A On the Reaction Rate Under the Uniform Distribution 623References 625Index 627