Molecular and Nano Electronics: Analysis, Design and Simulation (eBook)

Jorge M. Seminario (Herausgeber)

eBook Download: PDF

2006 | 1. Auflage
292 Seiten
Elsevier Science (Verlag)
978-0-08-046583-8 (ISBN)

Infos

The aim of Molecular and Nano Electronics: Analysis, Design and Simulation is to draw together contributions from some of the most active researchers in this new field in order to illustrate a theory guided-approach to the design of molecular and nano-electronics. The field of molecular and nano-electronics has driven solutions for a post microelectronics era, where microelectronics dominate through the use of silicon as the preferred material and photo-lithography as the fabrication technique to build binary devices (transistors). The construction of such devices yields gates that are able to perform Boolean operations and can be combined with computational systems, capable of storing, processing, and transmitting digital signals encoded as electron currents and charges. Since the invention of the integrated circuits, microelectronics has reached increasing performances by decreasing strategically the size of its devices and systems, an approach known as scaling-down, which simultaneously allow the devices to operate at higher speeds.

* Provides a theory-guided approach to the design of molecular and nano-electronics
* Includes solutions for researchers working in this area
* Contributions from some of the most active researchers in the field of nano-electronics

Inhalt

Front Cover 1
Table of Contents 6
Preface 7
Chapter 1 Metal–molecule–semiconductor junctions: an ab initio analysis 8
1. Introduction 8
2. Electron transport at interfaces 9
2.1. Electronic properties of molecules and clusters 9
2.1.1. Basis functions 10
2.1.2. Density functional theory 10
2.1.3. Molecular electrostatic potential 13
2.2. Electronic properties of crystalline materials 13
2.2.1. DOS of Au and Pd crystals 14
2.2.2. DOS of silicon crystal 15
2.2.3. DOS of the (4, 4) CNT 16
2.3. Combined DFT-GF approach to calculate the DOS of a molecule adsorbed on macroscopic contacts 17
3. Electron transport in molecular junctions 21
4. Metal–molecule–metal junctions 24
4.1. Metal–benzene–metal junction 24
4.2. Metal–nitroOPE–metal junction 26
5. Metal–molecule–semiconductor junctions 30
5.1. Significance of the electronic chemical potential (Fermi level) for a single molecule 31
5.2. Fermi-level alignmentŽ in metal.semiconductor interfaces 33
5.3. Quantum-mechanical calculation 35
5.3.1. Gold contact 35
5.3.2. (4, 4) CNT contact 36
5.3.3. Mulliken charges 39
5.4. Current–voltage calculation 40
5.4.1. Gold contact 40
5.4.2. (4, 4) CNT contact 41
5.5. Changes in the conformation and charge states 43
5.5.1. Gold contact 44
5.5.2. (4, 4) CNT contact 45
5.5.3. ESP distribution along the junction 47
5.5.4. Analysis of the molecular orbitals 48
6. Summary and conclusions 49
Acknowledgements 56
References 57
Chapter 2 Bio-molecular devices for terahertz frequency sensing 62
1. THz sensing science motivation and requirements 63
1.1. THz sensing science issues for bio-systems 63
1.2. Multiplication of THz phonon mode information in bio-systems 65
1.3. Acquisition of THz phonon mode information from bio-systems 66
2. Bio-molecular architectural concept and bio-component studies 68
2.1. Bio-molecular inspired architecture for sensing 69
2.2. Bio-component modeling and simulation 70
2.2.1. Simulation and analysis of butene isomers 71
2.2.2. Simulation and analysis of retinal isomers 76
3. Retinal nanostructure arrays 80
3.1. Two-dimensional nanopatterned retinal structure 80
3.2. Simulation and analysis of retinal derivatives 81
4. Directions for future work and conclusions 85
References 85
Chapter 3 Charge delocalization in (n, 0) model carbon nanotubes 89
1. Introduction 89
2. Electrostatic potential 90
3. Average local ionization energy 91
4. Computational procedure 92
5. Electrostatic potentials of model carbon nanotubes 93
6. Average local ionization energies on model carbon nanotube surfaces 97
7. Polarization of unsubstituted model carbon nanotubes 97
8. Why? 98
9. A possible application: Nonlinear optics 99
10. Concluding remarks 100
References 100
Chapter 4 Analysis of programmable molecular electronic systems 103
1. Introduction 103
1.1. Importance and current status of high speed electronics 103
1.1.1. Limitations in device fabrication 104
1.1.2. Limitations in device operation 104
1.2. Future perspective of electronics 105
2. Programmable molecular arrays 106
2.1. Introduction to programmable molecular cells 107
2.2. Sample fabrication 108
2.2.1. Substrate fabrication 108
2.2.2. Formation of self-assembled monolayers on nanoCell 109
2.3. Measurement set-up 110
2.4. Electrical characteristics of nanoCells 111
2.4.1. Transition states before NDR 113
2.4.2. Memory phenomenon in nanoCells 114
2.5. Influence of molecules on electrical behavior 115
2.6. Programming of nanoCell 117
3. Electrical conductance of discontinuous metallic film 119
3.1. Theoretical models in discontinuous metallic film 119
3.2. Electron transport through discontinuous metallic film below activation energy 120
3.3. NDR region beyond threshold voltage 122
3.4. Effects of morphology of discontinuous gold film 123
4. Static and transient current–voltage characteristics at the nanoscale 123
4.1. Standard transient response of conventional systems 123
4.2. Set-up of transient response measurement 125
4.3. Atomic scale response of discontinuous gold films 125
4.4. Time-dependent NDR and hysterisis 127
5. Vibronics and molecular potential 128
5.1. Limitations of charge–current transport as a method for signal transmission 128
5.2. Previous research work related to vibronics 128
5.3. Molecular dynamics simulation 129
5.4. DSP techniques for encoding and decoding signals 129
5.4.1. Modulation techniques 129
5.4.2. Decoding information 130
5.4.3. Recovering amplitude-modulated signal 130
5.4.4. Recovering frequency-modulated signal 132
5.5. Simulation results of molecular vibrational signal transmission 134
5.5.1. Amplitude-modulated signal transmission 135
5.5.2. Time delay of molecular vibrational signal transmission using AM 136
5.5.3. Noise and attenuation of molecular vibrational signal transmission using AM 137
5.5.4. Effects of different carrier frequencies on AM signal transmission 137
5.5.5. Molecular vibrational signal transmission using frequency modulation 138
5.6. Using molecular potential to process information 139
6. Conclusion and perspectives 141
7. Acknowledgements 143
References 143
Chapter 5 Modeling molecular switches:A flexible molecule anchored to a surface 148
1. Introduction 148
2. Various types of molecular switches 149
3. Molecules with amide groups – Conductance switching in applied electric fields 152
4. N-(2-mercaptoethyl)benzamide on Au(111): A reversible molecular switch 152
4.1. Free and adsorbed conformations 153
4.2. Bistability and hysteresis 154
5. Conductance switching in a photoisomeric azobenzamide molecule 158
6. Possible conformational changes of the azobenzamide molecule 160
7. Study of the azobenzamide molecule in applied electric field 161
7.1. Adsorbed conformations 161
7.2. Electric-field-dependent conformation changes 162
7.3. Possible effects of intermolecular coupling 164
8. Other interesting molecules for switching 165
9. Concluding remarks 166
Acknowledgements 166
References 166
Chapter 6 Semi-empirical simulations of carbon nanotube properties under electronic 170
1. Introduction 170
2. Background 171
2.1. Geometry of CNTs 171
2.2. Tight-binding description 172
2.3. Self-consistent formalism 173
3. Metal–semiconductor transition in carbon nanotubes 175
3.1. Model formulation 176
3.2. Gapping of A-SWNTs 177
3.3. Renormalization of the Fermi velocity 180
3.4. Combination of perturbations 180
4. Finite-size effect of carbon nanotubes 182
4.1. Structure and atomic partial charges 183
4.2. Band gap oscillation 185
4.3. Dielectric responses 186
4.4. Examples: Short CNTs in biological applications 187
5. Conclusion 191
Acknowledgements 192
References 192
Chapter 7 Nonequilibrium Green’s function modeling of the quantum transport of molecular electronic devices 194
1. Introduction 194
2. Review of methodology 195
3. Transport through prototypical molecular electronic devices 199
4. Current theoretical developments 208
5. Summary 208
Acknowledgements 209
References 209
Chapter 8 The gDFTB tool for molecular electronics 212
1. Introduction 212
2. DFTB as a semi ab-initio approach 213
3. The non-equilibrium Green’s function technique 215
4. Real contact and virtual contact currents 220
5. The Poisson equation 221
6. Applications to molecular conductance 223
7. Analysis of IETS spectra 225
8. Power dissipation in molecular junctions 228
9. GW corrections and transport 229
10. Applications to CNT devices 233
10.1. Screening properties of CNTs 234
10.2. Output characteristics 235
11. Conclusions 237
Acknowledgments 238
References 238
Chapter 9 Theory of quantum electron transport through molecules as the bases of molecular devices 240
1. Introduction 240
2. Non-equilibrium Green’s function with tight-binding bases 241
3. Effects of the linkage structure on the conductance of molecular bridges 242
4. Internal large loop currents 244
5. Effect of electron–phonon coupling 247
6. Carrier transport process 251
References 253
Chapter 10 Time-dependent transport phenomena 254
1. Introduction 254
2. The Keldysh formalism 256
2.1. The Keldysh contour 256
2.2. The Keldysh–Green function 258
2.3. The Keldysh book-keeping 259
3. Quantum transport using TDDFT and NEGF 261
3.1. Merging the Keldysh and TDDFT formalisms 261
3.2. Total current using TDDFT 263
3.3. Steady state and history dependence 265
4. Quantum transport: A practical scheme based on TDDFT 269
4.1. Computation of KS eigenstates 271
4.2. Algorithm for the time evolution 272
5. Implementation details for one-dimensional systems and numerical results 276
5.1. DC bias 280
5.2. Time-dependent biases 282
5.3. History dependence 284
5.4. Pumping current: Preliminary results 285
6. Conclusions and perspectives 288
Acknowledgments 289
References 290
Index 292

Produkt-Details

• Erscheint lt. Verlag: 24.10.2006
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber
• Themenwelt: Naturwissenschaften ► Biologie
• Themenwelt: Naturwissenschaften ► Chemie ► Physikalische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Quantenphysik
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• ISBN-10: 0-08-046583-8 / 0080465838
• ISBN-13: 978-0-08-046583-8 / 9780080465838