Single-Molecule Electronics (eBook)

Prof. Manabu KiguchiDepartment of Chemistry,Graduate School of Science and Engineering,Tokyo Institute of Technology,Tokyo,JAPAN

Preface 6
Contents 8
1 Molecular Electronics: A Brief Overview of the Status of the Field 9
1.1 Definition of Molecular Electronics 9
1.2 A Brief History 10
1.2.1 Molecular Monolayers: Langmuir-Blodgett Technique 10
1.2.2 Molecular Monolayers: Self-Assembly 12
1.2.3 Single Molecules 13
1.2.4 Present Status of the Field 14
1.3 Will Self-Assembled Molecular Circuits Replace Silicon? 17
1.4 Intrinsically Quantum 19
1.5 Challenges for Applications 20
1.6 Challenges for Fundamental Understanding 24
1.7 Outlook and Conclusions 25
References 26
2 Methods to Determine Electrical Conductance of Single-Molecule Junctions 32
2.1 Introduction 32
2.2 Mechanical Break Junction Method 33
2.2.1 Principle and Instruments for the Break Junction Method 33
2.2.1.1 Scanning Tunneling Microscope-Break Junction (STM-BJ) 34
2.2.1.2 Mechanically Controllable Break Junction 39
2.2.2 Statistical Data Analysis 42
2.2.2.1 Distance and Conductance: Two-Dimensional Histogram 42
2.2.2.2 Cross Correlation and Conditional Histogram Analysis 44
2.2.3 Related Techniques 46
2.2.3.1 Distance Modulations 46
2.2.3.2 Electromechanical Responses 48
2.2.3.3 Electrical and Electrolyte Gating 50
2.3 Other Experimental Methods to Prepare Single-Molecule Junctions 54
2.3.1 Electromigration Technique 54
2.3.2 Ultrahigh-Vacuum and Low-Temperature Scanning Tunneling Microscope 57
2.4 Summary and Perspective 60
References 62
3 Characterization of the Single Molecular Junction 67
3.1 Introduction 67
3.1.1 Plateau Length Analysis 68
3.1.2 Point-Contact Spectroscopy and Inelastic Electron Tunneling Spectroscopy 71
3.1.3 Surface-Enhanced Raman Scattering 76
3.1.4 Current–Voltage Characteristics 79
3.1.5 Thermopower Measurement 82
3.1.6 Shot-Noise Measurement 83
3.1.7 Force Measurement 85
3.2 Summary and Future Perspective 88
References 90
4 Molecular Wires: An Overview of the Building Blocks of Molecular Electronics 92
4.1 Introduction 92
4.2 Saturated Hydrocarbon Wires 97
4.3 Oligo(enes) and Oligo(ynes) 102
4.4 Oligo(arylenes) 106
4.5 Oligo(phenylene ethynylenes) and Oligo(phenylene vinylenes) 111
4.6 Summary and Outlook 115
References 116
5 Insulated Oligothiophenes 122
5.1 Introduction 122
5.2 Oligothiophenes with Bulky Silyl Substituents as Insulating Units 124
5.3 Completely Insulated Oligothiophenes with Anchor Units 127
5.4 Insulation-Tuned Oligothiophenes 133
5.5 Insulated Oligothiophenes with Hopping Conduction 137
5.6 Insulated Oligothiophenes with Electron-Affinity Characteristics 138
5.7 Summary 139
References 141
6 Synthesis and Physical Properties of Three-Dimensionally Insulated Molecular Wires 145
6.1 Introduction 145
6.2 Synthesis of Three-Dimensionally Insulated Molecular Wires 147
6.2.1 Synthesis of Cyclodextrin-Based Insulated Molecular Wires 147
6.2.2 Synthesis of Permethylated Cyclodextrin-Based Insulated Molecular Wires 149
6.2.3 Synthesis of Insulated Molecular Wires with High Charge Mobility 151
6.2.4 Synthesis of Functionalized Insulated Molecular Wires 153
6.2.5 Synthesis of Insulated Metallopolymers 155
6.2.5.1 Synthesis of Solid-State Phosphorescence Insulated Metallopolymers 157
6.2.5.2 Synthesis of One-Dimensional Insulated Coordination Polymers 159
6.3 The Establishment of Wiring Methods Utilizing Organic Reactions Between Nanosized Gaps 161
6.4 Summary and Conclusions 164
References 166
7 Orbital Rule for Electron Transport of Molecular Junctions 169
7.1 Introduction 169
7.2 Tight-Binding Model for Molecular Junctions 171
7.2.1 Two-Site Model 174
7.2.2 Three-Site (Triangular) Model 179
7.2.3 Orbital Rule from Experimental Observations 183
7.2.4 Spin-Dependent Transport in Molecular Spin Junctions 184
7.2.4.1 Coherent Approach for the Spin-Flip Process 187
7.2.4.2 Incoherent Approach for the Spin-Flip Process 191
7.3 Summary 192
References 193
8 Theoretical Aspects of Quantum Transport and Computational Modeling of Molecular Electronic Device 195
8.1 Introduction 195
8.2 Theory of Electric Transport in Molecular Junctions 196
8.2.1 Length Dependence of Conductance and Charge Migration Mechanisms 198
8.2.2 Universal Temperature Dependence Crossover and Inelastic Scattering Effect by Electron-Vibron Interaction 202
8.2.3 MO Engineering and Contact Chemistry via First-Principles Calculations 205
8.3 Rectification by a Single pn Molecule with Symmetric Anchors and Electrodes: Aviram-Ratner or Ellenbogen-Love Diode? 211
8.4 Summary 215
References 216
9 Single-Molecule Sequencing 221
9.1 Introduction 221
9.2 DNA Structures 223
9.3 The Principle of Single-Molecule Sequencing 224
9.4 Measurement and Analysis Methods 226
9.5 Single-Molecule Identification of Base Molecules 228
9.6 DNA Sequencing 230
9.7 RNA Sequencing 231
9.8 Peptide Sequencing 232
9.9 Perspective 237
References 238