Electroluminescence

PrefaceChapter 1. General Survey 1.1 Electro-Photoluminescence 1.1.1 Gudden-Pohl and Déchêne Effects 1.1.2 Recent Experiments on Field Effects 1.2 Basic Observations of Electroluminescence 1.2.1 General Considerations 1.2.2 Early Investigations on Detector Contacts 1.2.3 First Observations of Electroluminescence in Powder Phosphors 1.2.4 Electroluminescence as a Primary Phenomenon 1.3 Electroluminescence Phenomena in Zinc Sulphide Phosphors 1.3.1 Relation Between Integrated Light Intensity and Applied Voltage 1.3.2 Relation Between Integrated Light Intensity and Frequency 1.3.3 Temperature Dependence of the Electroluminescent Response 1.3.4 Brightness Waves 1.3.5 Spectral Composition 1.3.6 Effect of Radiation on Electroluminescence 1.4 Electroluminescence Phenomena in Various Materials 1.4.1 Silicon Carbide 1.4.2 III-V Compounds 1.4.3 Diamond 1.4.4 Barium and Strontium Titanates; Cuprous Oxide 1.4.5 Organic CompoundsChapter 2. Theoretical Models 2.1 Introduction 2.1.1 General Considerations 2.1.2 Limitations of the Band Model 2.2 Carrier Injection and Accumulation 2.2.1 Current-Controlled Non-Equilibrium Processes 2.2.2 Injection Properties of Metal Contacts 2.2.3 Injection Properties of Junctions 2.2.4 Semiconductor-Semiconductor Contacts 2.3 Impact Ionization 2.3.1 "Hot" Electrons 2.3.2 Ionization of Activator Centres 2.3.3 Ionization Probability and Electroluminescent Brightness 2.4 Localized Field Enhancement 2.4.1 Geometrical Spreading Resistances 2.4.2 Barrier Fields 2.4.3 Junction Fields 2.4.4 Polarization Effects 2.5 Polarization of Free Charge Carriers 2.5.1 Simplest Relaxation Conditions 2.5.2 Complicating Features of Practical Systems 2.5.3 Dispersive Behaviour of Space Charge Systems 2.5.4 Formation and Distribution of Polarization Space Charges 2.6 Outline of Junction Breakdown Theory 2.6.1 Experimental Basis 2.6.2 Zener Effect and Avalanche Processes 2.6.3 Ionization of the Crystal Lattice 2.7 Carrier Recombination: Qualitative Considerations 2.7.1 Recombination in a Perfect Lattice 2.7.2 Relaxation of an Excited Activator Centre 2.7.3 Recombination Through Activator Centres in the Presence of Carrier Injection or Accumulation 2.7.4 Delayed Recombination; Trapping 2.8 Phosphor Suspensions 2.8.1 Dielectric Constant and Field Distribution 2.8.2 Phase Relations and Dielectric LossChapter 3. Experiments on Single Crystal Phosphors (ZnS : Cds) 3.1 Preparation and Structure 3.1.1 Growth of Zinc Sulphide Crystals 3.1.2 Control of Impurity Content in Zinc Sulphide Crystals 3.1.3 Structural Characteristics of Zinc Sulphide Crystals 3.1.4 Growth and Structure of Cadmium Sulphide Crystals 3.1.5 Activation of Cadmium Sulphide Crystals 3.2 Contact Properties and Space Charge Effects 3.2.1 Contacts on Zinc Sulphide 3.2.2 Voltage Distribution Inside Single Crystals of Zinc Sulphide 3.2.3 Contacts on Cadmium Sulphide 3.2.4 Space Charges Near Contacts on Cadmium Sulphide 3.2.5 Probe Measurements on Cadmium Sulphide 3.3 Electroluminescence Effects in Zinc Sulphide Crystals 3.3.1 Location of the Emission Sources and Activation Studies Near Contacts 3.3.2 Observations of Anisotropy 3.3.3 Excitation by Constant Fields 3.3.4 Excitation by Alternating Fields 3.3.5 Excitation By Half-Wave Fields; Crystals without Cathode Barriers 3.3.6 Pulse Measurements on Crystals with Prominent Cathode Barriers 3.3.7 Field-Dependent Thermoluminescence 3.3.8 Electroluminescence at Very High Frequencies 3.4 Mechanisms of Electroluminescence in Zinc Sulphide Crystals 3.4.1 Origin of the Anisotropy 3.4.2 Choice of Excitation and Relaxation Processes 3.4.3 Origin and Timing of Emission Peaks 3.4.4 Behaviour of Field Ionizing Cathode Barriers 3.5 Electroluminescence Effects in Single Crystals of Cadmium Sulphide 3.5.1 Observations in the Pre-Breakdown Region 3.5.2 Observations Under Low Constant Field ExcitationChapter 4. Electroluminescence at Crystal Boundaries 4.1 Injection Electroluminescence in Germanium and Silicon 4.1.1 Behaviour of Injecting Boundaries 4.1.2 Emission Due to Injected Carriers 4.1.3 Structure of the Emission Spectra 4.1.4 Emission Due to Recombination in Surface States 4.2 Junction Breakdown Electroluminescence in Silicon and Germanium 4.2.1 Emission from Silicon p-n Junctions Under Reverse Bias 4.2.2 Electrical Breakdown and Light Emission Microplasmas 4.2.3 Emission from Germanium p-n Junctions Under Reverse Bias 4.3 Contact and Junction Electroluminescence in Silicon Carbide 4.3.1 Preparation of Silicon Carbide Crystals 4.3.2 Structural Features of Experimental Specimens 4.3.3 Spectral Response and Delay Time of Injection Electroluminescence 4.4 Boundary Electroluminescence Effects in Gallium Phosphide and Cadmium Telluride 4.4.1 Electro-Optical Observations; GaP 4.4.2 Observations of Spectral Characteristics; GaP 4.4.3 Injection Electroluminescence in Cadmium TellurideChapter 5. Experiments on Microgrystalline Phosphors 5.1 Preparatory Techniques—Structure of Electroluminescent Powders 5.1.1 Preparation of Copper-Activated Zinc Sulphide Phosphors 5.1.2 Zinc Sulphide Phosphors with Multiple Activators 5.1.3 Heterogeneity of Phosphor Grains 5.1.4 Structural Characteristics of Zinc Sulphide Phosphors 5.1.5 Control of Spectral Response By Choice of Parent Lattice 5.2 Excitation by Unidirectional Fields 5.2.1 Electroluminescent Emission on Application and Removal of Constant Fields 5.2.2 Effect of Pre-Excitation 5.2.3 Experiments with Unidirectional Periodic Fields; The Transport Polarization Model 5.2.4 Experiments with Single-Pulse Unidirectional Fields 5.2.5 Evidence for Transfer Ionization 5.3 Excitation by Alternating Fields 5.3.1 Short-Term Electroluminescent Build-Up 5.3.2 Voltage-Current and Voltage-Brightness Relations; Comparisons with Photoluminescence 5.3.3 Interpretation of Brightness Waves 5.3.4 Dielectric Properties of Phosphor Suspensions; Experiments 5.3.5 Experiments with Non-Sinusoidal Alternating Fields 5.3.6 Frequency Dependence of Electroluminescent Emission 5.3.7 Interaction of d.c. and a.c. Excitation 5.3.8 Long-Term Build-Up and Ageing Processes 5.4 The Study of Single Electroluminescent Grains and Thin Films 5.4.1 Luminescence Patterns and Brightness Waves in Single Grains of Zinc Sulphide 5.4.2 Experiments on Thin Films 5.5 Contact Electroluminescence 5.5.1 Experiments with Metal-Phosphor Mixtures 5.5.2 The Two-Phase Hypothesis of Electroluminescent Powder PhosphorsChapter 6. Electroluminescent Devices 6.1 Electroluminescent Light Sources 6.1.1 Construction of Test Cells and Panels 6.1.2 Performance and Stability 6.1.3 Brightness and Grain Size 6.1.4 Summary of Special Characteristics 6.2 Applications of Electroluminescent Panels 6.2.1 Illumination and Information Display 6.2.2 Controlled Electroluminescence 6.2.3 Radiation Amplification Through Photo-Electroluminescence 6.3 Association of Electroluminescent and Photoconductive Circuit Elements 6.3.1 Monostable and Bistable Optrons 6.3.2 Radiation Amplification by Means of Optrons 6.3.3 Opto-Electronic Networks 6.3.4 Static Display Screens with Photoconductive Control 6.3.5 Approximate Theory of Light Amplifiers 6.3.6 Storage Light Amplifiers 6.4 Scanned Picture Display Screens 6.4.1 General Problems 6.4.2 Display Screens with Ferroelectric Control 6.4.3 Display Screens with Magnetic Transfluxor Control 6.4.4 Display Screens with Piezovoltaic ControlBibliography on Electroluminescence and Related PhenomenaIndex