Bonds and Bands in Semiconductors

Preface1 Crystal Structures What Is a Semiconductor? Energy Bands Metals, Insulators, and Semiconductors Allowed and Forbidden Energies Valence Bonds Bond Counting Atomic Orbitals Hybridized Orbitals Bonding Definitions and Rules Bond Energy Gaps and Band Energy Gaps Tetrahedral Coordination Layer Structures Fluorite Bonds Relativistic Structures Chalcogenides Defect and Excess Compounds Transition Metal Semiconductors Bond Lengths and Radii Rationalized Radii Impurity Radii Layer Bonds Summary References2 Covalent and Ionic Bonds Electronic Configurations of Atoms Core d Electrons Universal Semiconductor Model Covalent and Ionic Character Symmetric and Antisymmetric Potentials Coulson Definition of Ionicity Pauling Definition of Ionicity Extension of Pauling's Definition to Crystals Limitations of Pauling's Definition The Middle Way Homopolar Energy Gaps Complex Energy Gaps and Resonance Heteropolar Energy Gaps Modern Definition of Ionicity Statistical Test of Definitions of Ionicity Borderline Crystals True (Undistorted) Scales Cohesive Energies Itinerant Character of Covalent Binding Core Corrections Electronegativity Table Historical Note Summary References3 Elastic and Piezoelectric Constants Stresses and Strains Harmonic Strain Energy Invariance Conditions Model Force Fields Diamond Lattice Zincblende Lattice Shear Constants and Ionicity Internal Strains Piezoelectric Constants Origin of Piezoelectric Effects Wurtzite Crystals Chalcopyrite Crystals Summary References4 Lattice Vibrations Brillouin Zones Experimental Determination of ω(k) Normal Modes Mode Descriptions Sum Rules Optically Active Modes Infrared Modes and Effective Charges Raman Active Modes Polaritons Dispersion Curves of Diamond-Type Semiconductors Electrostatic Models Zincblende-Type Dispersion Curves Metallization in Gray Sn Thermal Expansion Vibrations of Impurity Atoms Summary References5 Energy Bands The Language of Band Theory Nearly Free Electron Model Valence Bands of Silicon Jones Zone Simplified Bands Isotropic Model Secular Equation Dielectric Function of Isotropic Model Important Anisotropies Conduction Bands Band-Edge Curvatures Perturbation Theory Special Cases Atomic Orbitals Specific Band Structures Diamond and Silicon Germanium and Gallium Arsenide Indium Antimonide and Arsenide Gray Tin and the Mercury Chalcogenides Effective Mass Parameters The PbS Family Summary References6 Pseudopotentials and Charge Densities Atomic Wave Functions Atomic Pseudopotentials Crystal Potential Crystal Wave Functions Pseudoatom Form Factors Metallic Binding Covalent Binding Ionic Binding Semiconductor Wave Functions Pseudocharge Densities Atomic Charges Bond Charges Partially Ionic Charge Distributions Conduction Band States Pressure Dependence of Band Edges Temperature Dependence of Energy Gaps Summary References7 Fundamental Optical Spectra One-Electron Excitations Line and Continuum (Band) Spectra Dielectric Function Sum Rules Direct Thresholds Germanium Photoemission Derivative Techniques Interband Energies Core d Electrons Spectroscopic Definitions of Valence Chemical Trends in Interband Energies Spin-Orbit Splittings Crystal Field Splittings Nonlinear Susceptibilities Summary References8 Thermochemistry of Semiconductors Cohesive Energies Pauling's Description Ionicity and Metallization Heats of Formation Entropies of Fusion The PbS or ANB10-N Family Pressure-Induced Phase Transitions Ideal Solutions Regular Solutions Pseudobinary Alloys Bowing Parameters Crystallization of Pseudobinary Alloys Virtual Crystal Model Optical Transitions in Elemental Alloys Energy Gaps in Pseudobinary Alloys Summary References9 Impurities Crystal Growth and Perfection Stoichiometry of Compound Semiconductors Shallow and Deep Impurity States Diffusion of Interstitial and Substitutional Impurities Distribution Coefficients Donors and Acceptors Isovalent Impurities Spherical (Hydrogenic) Models Band-Edge Degeneracies Valleys Anisotropies Chemical Shifts and Central Cell Corrections Impurity States in Compound Semiconductors Free and Bound Excitons Donor-Acceptor and Isovalent Pairs Self-Compensation Polyvalent Impurities Transition Metal Impurities Summary References10 Barriers, Junctions, and Devices Fermi Levels Band Bending Metal-Semiconductor Contacts p-n Junctions Carrier Injection and Trapping Junction Transistors Tunnel Diodes Avalanche Diodes Why Si? Microwave Evolution Luminescence Junction Lasers Intervalley Transfer Oscillators Semiconductors and Materials Science ReferencesAuthor IndexSubject Index