Zinc Oxide. & Springer. Jean Geurts. Claus R Klingshirn. Andreas Waag Axel Hoffmann. Bruno K. Meyer. Towards Novel Applications

Transcription

1 Claus R Klingshirn Bruno K. Meyer Axel Hoffmann Jean Geurts Zinc Oxide From Fundamental Properties Towards Novel Applications With 226 Figures & Springer

2 Contents 1 Introduction 1 I. I History of ZnO Research and Contents of This Book Aim of This Review 4 References 5 2 Crystal Structure, Chemical Binding, and Lattice Properties 7 J. Geurts 2.1 Crystal Structure and Chemical Binding ZnO Polytype Structures Phase Transitions Crystal Axis Polarity Thermal Properties Thermal Expansion Coefficients Specific Heat Thermal Conductivity The Piezoelectric Effect Principle and Applications The Piezoelectric Tensor Lattice Dynamics Phonon Symmetry and Eigenvectors of the Wurtzite Lattice Phonon Dispersion Relations Infrared Optical Phonon Spectroscopy Raman Spectroscopy of Phonon Modes Vibration Modes in Doped ZnO Incorporation of Transition Metal Atoms in ZnO Raman Scattering from ZnO Nanoparticles Phonon-Plasmon Mixed States Collective Charge-Carrier Oscillations Coupling to Polar Longitudinal Phonons 33 References 35 IV ix

3 x Contents 3 Growth Bulk Growth Vapor Phase Transport Solvothermal Growth Epitaxial Growth Techniques Metal Organic Chemical Vapor Deposition Molecular Beam Epitaxy Pulsed Laser Deposition Growth of Self-Organized Nanostructures Growth Techniques for Nano Pillars Properties of Nanopillars 67 References 73 4 Band Structure 77 B. K. Meyer 4.1 The Ordering. of the Bands at the Valence Band Maximum in ZnO ZnO and Its Alloys Cationic Substitution: Mg, Cd, Be in ZnO Anionic Substitution: S, Se in ZnO Valence and Conduction Band Discontinuities lso-valent Hetero-Structures Hetero-Valent Hetero-Structures 92 References 93 5 Electrical Conductivity and Doping Introduction Hydrogen in ZnO Donors in ZnO: Al, Ga, In Acceptors in ZnO Mobility Ohmic and Schottky Contacts on ZnO Two-Dimensional Electron Gas and Quantum Hall Effect High-Field Transport and Varistors Photoconductivity 114 References Intrinsic Linear Optical Properties Close to the Fundamental Absorption Edge Free Excitons in Bulk Samples Free Excitons in Bulk Samples, Epitaxial Layers, and NanoRods Experimental Observations ZnO-Based Alloys 145

4 Contents xi 6.3 Surface Exciton Polaritons Excitons in Structures of Reduced Dimensionality Excitons in Quantum Wells and Superlattices Quantum Wires Quantum Dots Cavity Polaritons 162 References Bound Exciton Complexes 169 B.K. Meyer 7.1 ZnO Luminescence: An Overview Neutral Donor Bound Excitons (A-Valence Band) and Their Two Electron Satellites Ionized Donor Bound Excitons (A-Valence Band) A Comparison of the Localization Energies with Theoretical Predictions (the Haynes Rule) Excited State Properties of the Bound Excitons Donor-Acceptor Pair Transitions 189 References Influence of External Fields 201 M.R. Wagner and A. Hoffmann 8.1 Excitons in Magnetic Fields Zeeman Effect Free and Bound Excitons Selection Rules for Zeeman Splitting of Exciton States in Magnetic Fields Symmetry of Exciton Hole States Excitons in Strain Fields Uniaxial Pressure Hydrostatic Pressure Biaxial In-Plane Strain 225 References Deep Centres in ZnO 233 A. Hoffmann, E. Malguth, and B.K. Meyer 9.1 The Green and Yellow Emission Bands Transition Metal Ions ZnO/V ZnO/Fe ZnO/Fe ZnO/Fe ZnO/Co ZnO/Ni ZnO/Cu Outlook 264 References 264

5 xii Contents 10 Magnetic Properties 10.1 General Overview of the Topic 10.2 Short Overview of the Situation in ZnO 269 References Nonlinear Optics, High Density Effects and Stimulated Emission Nonlinear Optics High Excitation Effects The Intermediate Density Regime Electron-Hole Plasma Processes for Stimulated Emission Bulk Samples and Epilayers Quantum Wells and Superlattices Nano Rods and Their Cavity Modes Quantum Dots and Random Lasing Cavity Modes, Photonic Crystals and Polariton Lasers 299 References Dynamic Processes Dephasing Dynamics Relaxation Dynamics Recombination Dynamics 314 References Past, Present and Future Applications Past Applications The Electro Fax Copy Ferrite Properties Present and Emerging Applications Cement, Rubber, Paint and Glazes Catalysts, Pharmaceutics, Cosmetics and Food Additives Electronics Gas Sensors TCO, Solar Cells and Some Further Applications Visions of Future Applications pn Junctions Light Emitting Diodes Field Emitters Spintronics 338 References 339

6 Contents xlu 14 Conclusion and Outlook Conclusions Outlook 348 References 349 Index 3-^