Preface ...................................................... xiii
Author ....................................................... xvii
Chapter 1 Introduction .......................................... 1
1.1 Introduction ............................................... 1
1.2 Classification of Materials ................................ 1
1.3 Crystalline Materials ...................................... 1
1.4 Ceramics, Metals and Alloys, and Polymers .................. 5
1.4.1 Bonding in Materials ................................ 5
1.5 Functional Classification of Materials ..................... 6
1.6 Crystal Structures ......................................... 6
1.7 Directions and Planes in Crystal Structures ............... 10
1.7.1 Miller Indices for Directions ...................... 10
1.7.2 Miller Indices for Planes .......................... 10
1.7.3 Miller-Bravais Indices for Hexagonal Systems ....... 10
1.7.4 Interplanar Spacing ................................ 11
1.8 Interstitial Sites or Holes in Crystal Structures ......... 13
1.9 Coordination Numbers ...................................... 13
1.10 Radius Ratio Concept ...................................... 14
1.11 Crystal Structures of Different Materials ................. 15
1.11.1 Structure of Sodium Chloride ....................... 15
1.11.2 Structure of Cesium Chloride ....................... 15
1.11.3 Diamond Cubic Structure ............................ 16
1.11.4 Zinc Blende Structure .............................. 18
1.11.5 Wurtzite Structure ................................. 19
1.11.6 Fluorite and Antifluorite Structure ................ 19
1.11.7 Corundum Structure ................................. 19
1.11.8 Perovskite Crystal Structure ....................... 20
1.11.9 Spinel and Inverse Spinel Structures ............... 21
1.12 Defects in Materials ...................................... 22
1.13 Point Defects in Ceramic Materials ........................ 23
1.14 Kröger-Vink Notation for Point Defects .................... 24
1.15 Dislocations .............................................. 26
1.16 Stacking Faults and Grain Boundaries ...................... 27
1.17 Microstructure-Property Relationships ..................... 28
1.17.1 Grain Boundary Effects ............................. 28
1.17.2 Grain Size Effects ................................. 28
1.17.3 Microstructure-Insensitive Properties .............. 30
1.18 Amorphous Materials ....................................... 30
1.18.1 Atomic Arrangements in Amorphous Materials ......... 30
1.18.2 Applications of Amorphous Materials ................ 31
1.19 Nanostructured Materials .................................. 33
1.20 Defects in Materials: Good News or Bad News? .............. 33
1.21 Problems .................................................. 33
1.19 Glossary .................................................. 34
References ..................................................... 37
Chapter 2 Electrical Conduction in Metals and Alloys .......... 39
2.1 Introduction .............................................. 39
2.2 Ohm's Law ................................................. 41
2.3 Sheet Resistance (Rs) ..................................... 46
2.4 Classical Theory of Electrical Conduction ................. 48
2.5 Drift, Mobility, and Conductivity ......................... 49
2.6 Electronic and Ionic Conductors ........................... 52
2.7 Limitations of the Classical Theory of Conductivity ....... 52
2.8 Resistivity of Metallic Materials ......................... 55
2.8.1 Effect of Thermal Expansion ........................ 60
2.9 Joule Heating or I2R Losses ............................... 60
2.10 Dependence of Resistivity on Thickness .................... 61
2.11 Chemical Composition-Microstructure-Conductivity
Relationships in Metals ................................... 62
2.11.1 Influence of Atomic-Level Defects .................. 62
2.11.2 Influence of Impurities ............................ 63
2.12 Resistivity of Metallic Alloys ............................ 66
2.13 Quantum Mechanical Approach to Conductivity ............... 69
2.14 Electrons in an Atom ...................................... 71
2.15 Electrons in a Solid ...................................... 72
2.16 Band Structure of Solids .................................. 73
2.17 Concept of the Fermi Energy Level ......................... 76
2.18 Problems .................................................. 77
Glossary ....................................................... 80
References ..................................................... 83
Chapter 3 Fundamentals of Semiconductor Materials ............. 85
3.1 Introduction .............................................. 85
3.2 Intrinsic Semiconductors .................................. 85
3.3 Temperature Dependence of Carrier Concentrations .......... 89
3.4 Band Structure of Semiconductors .......................... 90
3.5 Direct and Indirect Bandgap Semiconductors ................ 96
3.6 Applications of Direct Bandgap Materials .................. 96
3.7 Motions of Electrons and Holes ........................... 100
3.8 Extrinsic Semiconductors ................................. 102
3.9 Donor-Doped (n-Type) Semiconductors ...................... 102
3.10 Acceptor-Doped (p-Type) Semiconductors ................... 103
3.11 Amphoteric Dopants, Compensation, and Isoelectronic
Dopants .................................................. 104
3.12 Dopant Ionization ........................................ 105
3.13 Conductivity of Intrinsic and Extrinsic Semiconductors ... 109
3.14 Effect of Temperature on the Mobility of Carriers ........ 111
3.15 Effect of Dopant Concentration on Mobility ............... 112
3.16 Temperature Dependence of Conductivity ................... 114
3.17 Effect of Partial Dopant Ionization ...................... 114
3.18 Effect of Temperature on the Bandgap ..................... 117
3.19 Effect of Dopant Concentration on the Bandgap (Eg) ....... 119
3.20 Effect of Crystallite Size on the Bandgap ................ 119
3.21 Semiconductivity in Ceramic Materials .................... 120
3.22 Problems ................................................. 121
Glossary ...................................................... 122
References .................................................... 124
Chapter 4 Fermi Energy Levels in Semiconductors .............. 127
4.1 Fermi Energy Levels in Metals ............................ 127
4.2 Fermi Energy Levels in Semiconductors .................... 129
4.3 Electron and Hole Concentrations ......................... 131
4.4 Fermi Energy Levels in Intrinsic Semiconductors .......... 134
4.5 Carrier Concentrations in Intrinsic Semiconductors ....... 136
4.6 Fermi Energy Levels in n-Type and p-Type
Semiconductors ........................................... 138
4.7 Fermi Energy as a Function of the Temperature ............ 140
4.8 Fermi Energy Positions and the Fermi-Dirac
Distribution ............................................. 143
4.9 Degenerate or Heavily Doped Semiconductors ............... 143
4.10 Fermi Energy Levels across Materials and Interfaces ...... 145
4.11 Problems ................................................. 147
Glossary ...................................................... 148
References .................................................... 149
Chapter 5 Semiconductor p-n Junctions ........................ 151
5.1 Formation of a p-n Junction .............................. 151
5.2 Drift and Diffusion of Carriers .......................... 154
5.3 Constructing the Band Diagram for a p-n Junction ......... 154
5.4 Calculation of Contact Potential ......................... 157
5.5 Space Charge at the p-n Junction ......................... 160
5.6 Electric Field Variation across the Depletion Region ..... 161
5.7 Variation of Electric Potential .......................... 162
5.8 Width of the Depletion Region and Penetration Depths ..... 164
5.9 Reverse-Biased p-n Junction .............................. 166
5.10 Diffusion Currents in a Forward-Biased p-n Junction ...... 167
5.11 Drift Currents in a p-n Junction ......................... 168
5.12 Diode Based on a p-n Junction ............................ 171
5.13 Reverse-Bias Breakdown ................................... 174
5.14 Zener Diodes ............................................. 178
5.15 Problems ................................................. 180
Glossary ...................................................... 181
References .................................................... 183
Chapter 6 Semiconductor Devices .............................. 185
6.1 Metal-Semiconductor Contacts ............................. 185
6.2 Schottky Contacts ........................................ 185
6.2.1 Band Diagrams ..................................... 185
6.2.2 Surface Pinning of the Fermi Energy Level ......... 188
6.2.3 Current-Voltage Characteristics for Schottky
Contacts .......................................... 189
6.2.4 Advantages of Schottky Diodes ..................... 193
6.3 Ohmic Contacts ........................................... 194
6.3.1 Band Diagram ...................................... 194
6.4 Solar Cells .............................................. 194
6.4.1 Principles of Operation ........................... 197
6.4.2 Current-Voltage Characteristics for a Solar
Cell .............................................. 201
6.4.3 Solar Cell Efficiency and Materials ............... 203
6.5 Light-Emitting Diodes .................................... 203
6.5.1 Operating Principle ............................... 204
6.5.2 LED Materials ..................................... 204
6.5.3 LEDs Based on Indirect Bandgap Materials .......... 206
6.5.4 LED Emission Spectral Ranges ...................... 207
6.5.5 I-V Curve for LEDs ................................ 208
6.5.6 LED Efficiency .................................... 210
6.5.7 LED Packaging ..................................... 210
6.6 Bipolar Junction Transistor .............................. 210
6.6.1 Principles of Operation of the Bipolar Junction
Transistor ........................................ 212
6.6.2 Bipolar Junction Transistor Action ................ 213
6.6.3 Current Flows in an npn Transistor ................ 213
6.6.4 Transistor Currents and Parameters ................ 215
6.6.4.1 Collector Current ........................ 215
6.6.4.2 Emitter Current .......................... 216
6.6.4.3 Base Current ............................. 216
6.6.5 Role of Base Current .............................. 218
6.6.6 Transistor Operating Modes ........................ 218
6.6.7 Current-Voltage Characteristics of the Bipolar
Junction Transistor ............................... 218
6.6.8 Current Flows in a pnp Transistor ................. 220
6.6.9 Applications of Bipolar Junction Transistors ...... 220
6.7 Field-Effect Transistors ................................. 223
6.8 Types of Field-Effect Transistors ........................ 223
6.9 MESFET I-V Characteristics ............................... 224
6.9.1 MESFET with No Bias ............................... 224
6.9.2 MESFET with a Gate Bias ........................... 225
6.10 Metal Insulator Field-Effect Transistors ................. 226
6.11 Metal Oxide Semiconductor Field-Effect Transistors ....... 226
6.11.1 MOSFET in Integrated Circuits ..................... 226
6.11.2 Role of Materials in MOSFET ....................... 226
6.11.3 NMOS, PMOS, and CMOS Devices ...................... 228
6.11.4 Enhancement-Mode MOSFET ........................... 229
6.11.5 Mechanism for Enhancement MOSFET .................. 230
6.11.6 Depletion-Mode MOSFET ............................. 232
6.12 Problems ................................................. 232
Glossary ...................................................... 234
References .................................................... 238
Chapter 7 Linear Dielectric Materials ........................ 239
7.1 Dielectric Materials ..................................... 239
7.1.1 Electrostatic Induction ........................... 239
7.2 Capacitance and Dielectric Constant ...................... 240
7.2.1 Parallel-Plate Capacitor Filled with a Vacuum ..... 240
7.2.2 Parallel-Plate Capacitors with an Ideal
Dielectric Material ............................... 242
7.3 Dielectric Polarization .................................. 249
7.4 Local Electric Field (Јlocal) ............................. 252
7.5 Polarization Mechanisms—Overview ......................... 254
7.6 Electronic or Optical Polarization ....................... 254
7.6.1 Electronic Polarization of Atoms .................. 254
7.6.2 Electronic Polarizability of Ions and Molecules ... 260
7.7 Ionic, Atomic, or Vibrational Polarization ............... 260
7.8 Shannon's Polarizability Approach for Predicting
Dielectric Constants ..................................... 262
7.8.1 Outline of the Approach ........................... 262
7.8.2 Limitations of Shannon's Approach ................. 263
7.9 Dipolar or Orientational Polarization .................... 265
7.10 Interfacial, Space Charge, or Maxwell-Wagner
Polarization ............................................. 266
7.11 Spontaneous or Ferroelectric Polarization ................ 267
7.12 Dependence of the Dielectric Constant on Frequency ....... 268
7.12.1 Connection to the Optical Properties:
Lorentz-Lorenz Equation ........................... 269
7.13 Complex Dielectric Constant and Dielectric Losses ........ 272
7.13.1 Complex Dielectric Constant ....................... 272
7.13.2 Real Dielectrics and Ideal Dielectrics ............ 273
7.13.3 Frequency Dependence of Dielectric Losses ......... 273
7.13.4 Giant Dielectric Constant Materials ............... 276
7.14 Equivalent Circuit of a Real Dielectric .................. 277
7.15 Impedance (Z) and Admittance (Y) ......................... 278
7.16 Power Loss in a Real Dielectric Material ................. 280
7.16.1 Concept of tan δ .................................. 280
7.17 Equivalent Series Resistance and Equivalent Series
Capacitance .............................................. 285
7.18 Problems ................................................. 288
Glossary ...................................................... 293
References .................................................... 298
Chapter 8 Ferroelectrics, Piezoelectrics, and
Pyroelectrics ...................................... 299
8.1 Ferroelectric Materials .................................. 299
8.1.1 Ferroelectricity in Barium Titanate ............... 299
8.1.2 Ferroelectric Domains ............................. 301
8.1.3 Dependence of the Dielectric Constant of
Ferroelectrics on Temperature and Composition ..... 303
8.2 Relationship of Ferroelectrics and Piezoelectrics to
Crystal Symmetry ......................................... 307
8.3 Electrostriction ......................................... 307
8.4 Ferroelectric Hysteresis Loop ............................ 309
8.4.1 Trace of the Hysteresis Loop ...................... 311
8.5 Piezoelectricity ......................................... 315
8.5.1 Origin of the Piezoelectric Effect in
Ferroelectrics .................................... 315
8.6 Direct and Converse Piezoelectric Effects ................ 317
8.7 Piezoelectric Behavior of Ferroelectrics ................. 318
8.8 Piezoelectric Coefficients ............................... 318
8.9 Tensor Nature of Piezoelectric Coefficients .............. 321
8.9.1 Conventions for Directions ........................ 321
8.9.2 General Notation for Piezoelectric Coefficients ... 322
8.9.3 Signs of Piezoelectric Coefficients ............... 322
8.10 Relationship between Piezoelectric Coefficients .......... 323
8.11 Applications of Piezoelectrics ........................... 327
8.12 Devices Based on Piezoelectrics .......................... 327
8.12.1 Expander Plate .................................... 327
8.13 Technologically Important Piezoelectrics ................. 333
8.14 Lead Zirconium Titanate .................................. 335
8.14.1 Piezoelectric Polymers ............................ 336
8.15 Applications and Properties of Hard and Soft Lead
Zirconium Titanate Ceramics .............................. 339
8.16 Electromechanical Coupling Coefficient ................... 341
8.17 Illustration of an Application: Piezoelectric Spark
Igniter .................................................. 344
8.18 Recent Developments ...................................... 348
8.18.1 Strain-Tuned Ferroelectrics ....................... 348
8.18.2 Lead-Free Piezoelectrics .......................... 348
8.19 Piezoelectric Composites ................................. 349
8.20 Pyroelectric Materials and Devices ....................... 351
8.20.1 Pyroelectric Detectors for Infrared Detection
and Imaging ....................................... 355
8.21 Problems ................................................. 355
Glossary ...................................................... 358
References .................................................... 361
Chapter 9 Magnetic Materials ................................. 363
9.1 Introduction ............................................. 363
9.2 Origin of Magnetism ...................................... 363
9.3 Magnetization (M), Flux Density (B), Magnetic
Susceptibility (χm), Permeability (μ), and Relative
Magnetic Permeability (μr) ............................... 368
9.3.1 Magnetic Field (H), Magnetization (M), and Flux
Density (B) ....................................... 368
9.3.2 Magnetic Susceptibility (χm) and Magnetic
Permeability (μ) .................................. 371
9.3.3 Demagnetizing Fields .............................. 372
9.3.4 Flux Density in Ferromagnetic and Ferrimagnetic
Materials ......................................... 373
9.4 Classification of Magnetic Materials ..................... 374
9.4.1 Diamagnetic Materials ............................. 374
9.4.2 Paramagnetic Materials ............................ 374
9.4.3 Superparamagnetic Materials ....................... 376
9.4.4 Antiferromagnetic Materials ....................... 378
9.5 Ferromagnetic and Ferrimagnetic Materials ................ 378
9.5.1 Hysteresis Loop ................................... 378
9.6 Other Properties of Magnetic Materials ................... 385
9.6.1 Curie Temperature (Tc) ............................ 385
9.6.2 Magnetic Permeability (μ) ......................... 385
9.6.3 Coercive Field (Hс) ............................... 386
9.6.4 Nucleation and Pinning Control of Coercivity ...... 388
9.6.5 Magnetic Anisotropy ............................... 389
9.6.6 Magnetic Domain Walls ............................. 391
9.6.7 180° and Non-180° Domain Walls .................... 393
9.6.8 Maximum Energy Products for Magnets ............... 394
9.6.9 Magnetic Losses ................................... 395
9.7 Magnetostriction ......................................... 396
9.8 Soft and Hard Magnetic Materials ......................... 397
9.9 Hard Magnetic Materials .................................. 398
9.10 Isotropic, Textured (Oriented), and Bonded Magnets ....... 399
9.11 Soft Magnetic Materials .................................. 400
9.12 Magnetic Data Storage Materials .......................... 404
9.13 Problems ................................................. 405
Glossary ...................................................... 408
References .................................................... 412
Index ......................................................... 413
|
