Nanophysics and Nanotechnology

Edward L. Wolf is Professor of Physics at the Polytechnic Institute of NYU. He is an expert on Nanotechnology, with a research background including Scanning Tunneling Microscopy. He has designed courses and written textbooks on Nanotechnology and Renewable Energy. His teaching includes modern physics, solid state physics, thermodynamics, and quantum mechanics. Professor Wolf is the author of more than a hundred papers in solid state physics, scanning tunneling microscopy, electron tunneling spectroscopy and superconductivity. He is Fellow of American Physical Society and received teaching and research awards at NYU Poly.

• Preface xvGlossary of abbreviations xvii1 Introduction 11.1 Nanometers, Micrometers, and Millimeters 31.1.1 Plenty of Room at the Bottom 41.1.2 Scaling the Xylophone 41.1.3 Reliability of Concepts and Approximate Parameter Values Down to About L = 10 nm (100 Atoms) 51.1.4 Nanophysics Built into the Properties of Bulk Matter 61.2 Moore’s Law 71.3 Esaki’s Quantum Tunneling Diode 91.4 QDs of Many Colors 101.5 GMR and TMR 100–1000 Gb Hard Drive “Read Heads” 111.6 Accelerometers in Your Car 141.7 Nanopore Filters 151.8 Nanoscale Elements in Traditional Technologies 15References 162 Systematics of Making Things Smaller, Pre-quantum 172.1 Mechanical Frequencies Increase in Small Systems 172.2 Scaling Relations Illustrated by a Simple Harmonic Oscillator 202.3 Scaling Relations Illustrated by Simple Circuit Elements 212.4 Thermal Time Constants and Temperature Differences Decrease 222.5 Viscous Forces Become Dominant for Small Particles in Fluid Media 222.6 Frictional Forces Can Disappear in Symmetric Molecular Scale Systems 24References 263 What Are Limits to Smallness? 273.1 Particle (Quantum) Nature of Matter: Photons, Electrons, Atoms, and Molecules 273.2 Biological Examples of Nanomotors and Nanodevices 283.2.1 Linear Spring Motors 293.2.2 Linear Engines on Tracks 303.2.3 Rotary Motors 333.2.4 Ion Channels, the Nanotransistors of Biology 363.2.4.1 Ca++-Gated Potassium Channel 373.2.4.2 Voltage-Gated Potassium Channel 373.3 How Small Can You Make it? 383.3.1 What Are the Methods for Making Small Objects? 393.3.2 How Can You See What You Want to Make? 393.3.3 How Can You Connect it to the Outside World? 423.3.4 If You Cannot See it or Connect to it, Can You Make it Self-Assemble and Work on its Own? 423.3.5 Approaches to Assembly of Small Three-Dimensional Objects 423.3.5.1 Variable Thickness Electroplating 433.3.5.2 Lithography onto Curved Surfaces 433.3.5.3 Optical Tweezers 433.3.5.4 Arrays of Optical Traps 453.3.6 Use of DNA Strands in Guiding Self-Assembly of Nanometer-Sized Structures 46References 484 Quantum Nature of the Nanoworld 514.1 Bohr’s Model of Nuclear Atom 524.1.1 Quantization of Angular Momentum 524.1.2 Extensions of Bohr’s Model 534.2 Particle–Wave Nature of Light and Matter, DeBroglie Formulas λ = h¨Mp, E = hν 544.3 Wavefunction Ψ for Electron, Probability Density Ψ ∗ Ψ, Traveling and Standing Waves 554.4 Maxwell’s Equations; E and B as Wavefunctions for Photons, Optical Fiber Modes 594.5 The Heisenberg Uncertainty Principle 604.6 Schrodinger Equation, Quantum States and Energies, Barrier Tunneling 614.6.1 Schrodinger Equations in One Dimension 624.6.1.1 Time-Dependent Equation 624.6.1.2 Time-Independent Equation 634.6.2 The Trapped Particle in One Dimension 634.6.2.1 Linear Combinations of Solutions 644.6.2.2 Expectation Values 644.6.2.3 Two-Particle Wavefunction 654.6.3 Reflection and Tunneling at a Potential Step 654.6.3.1 Case 1: E > Uo 664.6.3.2 Case 2: E