Organic Nanostructures for Next Generation Devices

by Al-shamery, Katharina; Rubahn, Horst-gunter; Sitter, Helmut

• ISBN13: 9783540719229
• ISBN10: 3540719229
• Format: Hardcover
• Copyright: 2008-03-05
• Publisher: Springer Nature

Summary

This book provides the first comprehensive overview of fabrication, fundamental properties and applications of a new class of nanoscaled organic materials which holds huge promise for future submicron-sized photonics and optoelectronics. By controlled self-assembled growth on single crystal surfaces, fiber-like structures are fabricated with macroscopic lengths up to millimeter size but mesoscopic widths of mere hundreds of nanometers and nanoscopic heights of several ten nanometers. The extraordinary beauty of these new structures is that they are quasi single crystalline, providing superior optical and electronic properties, and that their properties can be freely tailored via functionalization of their organic building blocks.

Table of Contents

List of Acronyms and Symbols	p. XVII
Introduction
Fundamentals of Organic Film Growth and Characterisation	p. 3
General	p. 3
Nucleation Process and Growth Modes	p. 4
The Surface Science Approach	p. 7
In Situ UHV MBE	p. 8
Valence Band Photoemission (ARUPS)	p. 9
Near Edge X-Ray Absorption Fine Structure Spectroscopy (NEXAFS)	p. 12
Scanning Tunnelling Microscopy	p. 14
Crystallography Characterisation	p. 15
Fundamentals of Atomic Force Microscopy	p. 16
References	p. 18
Optical Characterization Methods for Ultrathin Nanoaggregates	p. 21
Dark Field and Fluorescence Microscopy	p. 21
Two-Photon Microscopy	p. 22
Scanning Near-Field Optical Microscopy	p. 24
Two-Photon Near-Field Microscopy	p. 25
References	p. 28
Growth
Growth of Oriented Organic Nanoaggregates via Molecular Beam Deposition	p. 31
Introduction	p. 31
Adsorbates	p. 32
Silicate Substrates	p. 34
Phenylenes on Muscovite	p. 36
Para-Hexaphenylene	p. 36
Steps and Defects	p. 43
Kinetics	p. 45
Growth Model	p. 51
Thiophenes on Muscovite	p. 53
Microrings	p. 56
Au-Mica Heterostructures	p. 58
Conclusions	p. 60
References	p. 62
Tailored Organic Nanoaggregates Generated by Self-Assembly of Designed Functionalised p-Quaterphenylenes on Muscovite Mica Substrates	p. 67
Introduction	p. 67
Design	p. 68
Synthesis of Oligomers	p. 70
Vapour Deposition Studies	p. 72
Nanoaggregates from Symmetrically Functionalised Oligomers	p. 73
Nanoaggregates from Non-Symmetrically Functionalised Oligomers	p. 78
Non-Linear Optical Properties	p. 80
Quantum Chemical Calculations and Optical Properties	p. 82
Conclusion	p. 83
References	p. 84
Hot-Wall Epitaxial Growth of Films of Conjugated Molecules	p. 89
Introduction: Why Highly Ordered Organic Thin Films?	p. 89
Experimental Setup	p. 90
Hot-Wall Epitaxy	p. 90
Source Materials and Substrates	p. 93
Characterization Methods	p. 94
Pristine and Ba-Doped Ceo Layers	p. 95
C60 Films on Mica Substrates	p. 95
Doping of C60 with Ba	p. 98
Highly Ordered Films of Para-Sexiphenyl	p. 100
Needles and Islands of p-6P on KCl Substrates	p. 102
Islands and Nanofibers of p-6P on Mica Substrates	p. 106
Conclusion	p. 114
References	p. 116
Crystallography of Ultrathin Organic Films and Nanoaggregates	p. 119
Overview	p. 120
Crystal Structure of Rodlike Conjugated Molecules	p. 122
Oligoacenes	p. 124
Oligophenylenes	p. 124
Oligothiophenes	p. 125
Experimental Methods	p. 126
Fundamentals	p. 126
Specular Scans	p. 127
Rocking Curves	p. 128
Pole Figure Technique	p. 130
Surface Diffraction	p. 131
Line Profile Analysis	p. 132
Transmission Electron Microscopy	p. 134
Crystallographic Order within Nanoaggregates	p. 137
Out-of-Plane Order	p. 138
In-Plane Order (Organic Epitaxy)	p. 140
Relation Between Crystal Structure and Film Morphology	p. 145
Crystallite Size	p. 148
Polymorphism	p. 152
Early Stage Growth	p. 153
Conclusion	p. 158
References	p. 159
Growth and Electronic Structure of Homo- and Hetero-epitaxial Organic Nanostructures	p. 165
Introduction	p. 165
Organic Films on Inorganic Substrates	p. 166
The Substrate as a Template	p. 167
Structure and Morphology Determinants: Sticking vs. Diffusion Anisotropy	p. 171
The Electronic Structure	p. 178
The Electronic Band Alignment on Nanostructured Interfaces	p. 182
Organic-Organic Heteroepitaxy	p. 185
Growth on Closed -CH-terminated Organic Surfaces	p. 186
Growth on Open ¿-terminated Organic Surfaces	p. 187
Outlook	p. 191
References	p. 191
Mechanisms Governing the Growth of Organic Oligophenylene "Needles" on Au Substrates	p. 195
Introduction	p. 195
Experimental	p. 197
The Importance of Molecular Conformations in P4P	p. 198
Molecular Orientation and Conformation within Ultrathin P4P Films Grown on Gold Substrates: Studies using Soft X-ray Absorption Spectroscopy	p. 198
Ultrathin Layer Containing only the ¿-Species	p. 199
Full Monolayer Containing ¿-and ß-Species	p. 202
Multilayers	p. 202
The Orientation of Organic Oligophenylene "Needles" on Gold Substrates	p. 203
Manipulation of Organic Needles Using an STM Operated under SEM Control	p. 206
STM Studies of P4P Needles	p. 207
Manipulation of STM Needles	p. 211
STM Investigations of the Former Contact Area	p. 214
References	p. 215
Optics
Nanooptics Using Organic Nanofibers	p. 219
Morphology and Optical Response	p. 219
Static Response	p. 219
Dynamic Response	p. 220
Guiding of Electromagnetic Waves	p. 225
Spatial Distribution of Molecular Emitters	p. 228
The Optical Near Field of Nanofibers	p. 231
Single Photon Tunneling Microscopy	p. 231
Two-photon Near Field Microscopy	p. 234
Conclusions	p. 236
References	p. 237
Optical Gain and Random Lasing in Self-Assembled Organic Nanofibers	p. 239
Introduction	p. 239
Overview on Random Lasing	p. 240
Experimental Techniques	p. 241
Random Lasing and Amplified Spontaneous Emission in Close-Packed Organic Nanofibers	p. 242
Optical Amplification and Random Laser Action in Single Organic Nanofibers	p. 247
Coherent Random Lasing in Single Nanofibers	p. 247
Optical Amplification in Single Nanofibers	p. 252
Potential Applications of Self-assembled Organic Nanofibers	p. 255
Summary and Conclusions	p. 257
References	p. 258
Applications
Fabrication and Characterization of Self-Organized Nanostructured Organic Thin Films and Devices	p. 263
Introduction	p. 263
Experimental Methods	p. 265
Organic Materials and Growth Techniques	p. 265
OFET: Device Fabrication	p. 266
Electrical Characterization Using an OFET (Operating Principle)	p. 267
Morphological Characterization of Organic Thin Films and Devices	p. 270
Optical and Structural Characterization of Organic Thin Films and Devices	p. 270
Anisotropy of Self-Organized Organic Thin Films	p. 271
Anisotropic Epitaxial Growth of p-6P on Mica(001)	p. 271
Anisotropic Epitaxial Growth of p-6P on KCl(001)	p. 277
Anisotropic Epitaxial Growth of p-6P and p-4P on TiO2 and Metal Surfaces	p. 282
Luminescent and Lasing Properties of Anisotropic Organic Thin Films	p. 285
Devices Based on Organic Thin Films	p. 288
OFETs Based on C60 Thin Films Grown by HWE	p. 288
Anisotropic Current-Voltage Characteristics of p-6P Chains on Mica	p. 292
Conclusions	p. 295
References	p. 296
Device-Oriented Studies on Electrical, Optical and Mechanical Properties of Individual Organic Nanofibers	p. 301
Introduction	p. 301
Toward Photonic Devices: The Optical Properties of Isolated Nanofibers	p. 303
Preparation and Optical Detection	p. 303
Nanofiber Tomography and Angular Light Emission	p. 304
Studies on Electrical Properties	p. 309
Charge Injection and Transport	p. 309
Experiments on Single-Nanofiber Devices	p. 311
Nanofiber Mechanics	p. 315
2-D Manipulation	p. 316
3-D Manipulation	p. 320
Conclusions	p. 322
References	p. 323
Device Treatment of Organic Nanofibers: Embedding, Detaching, and Cutting	p. 325
Introduction	p. 325
Coating of Organic Nanofibers on Mica	p. 327
Parameters Related to the Embedding of Organic Nanofibers: Thermal Conductivity and Thermal Expansion	p. 327
Evaporation of Silicon Oxide	p. 329
Antibleaching Effect with SiOx Coatings	p. 330
Microscopical Analysis of Nanofibers on Mica, Covered by SiOx	p. 330
Parameters Related to the Embedding of Organic Nanofibers: Preparation of Polymer Films	p. 338
Motivation for Encapsulation of Nanofibers in Polymers	p. 338
Essential and Desirable Polymer Properties, Preparation Strategies	p. 340
Cutting of Nanofibers	p. 342
Conclusions	p. 345
References	p. 346
Index	p. 347
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