PART Ⅰ:PREPARATION AND MATERIALS 3
LANGMUIR-BLODGETT FILMS 3
1.1 Introduction 3
1.2 L-B Films of Long-Chain Compounds 6
Fatty Acids 6
Amines 8
Other Long-Chain Compounds 8
1.3 Cyclic Compounds and Chromophores 9
1.4 Polymers and Proteins 10
1.5 Polymerization In Situ 11
1.6 Alternation Films(Superlattices) 12
1.7 Potential Applications 13
SELF-ASSEMBLED MONOLAYERS 21
2.1 Introduction 21
2.2 Monolayers of Fatty Acids 22
2.3 Monolayers of Organosilicon Derivatives 22
2.4 Monolayers of Alkanethiolates on Metal and Semiconductor Surfaces 24
2.5 Self-Assembled Monolayers Containing Aromatic Groups 27
2.6 Conclusions 28
PART Ⅱ:ANALYSIS OF FILM AND SURFACE PROPERTIES 35
SPECTROSCOPIC ELLIPSOMETRY 35
3.1 Introduction and Overview 35
3.2 Theory of Ellipsometry 36
3.3 Instrumentation 38
3.4 Determination of Optical Properties 40
Analysis of Single Ellipsometric Spectra:Direct Inversion Methods 40
Analysis of Single Ellipsometric Spectra:Least-Squares Regression Analysis Method 42
Analysis of Multiple Ellipsometric Spectra 44
3.5 Determination of Thin Film Structure 46
Thickness Determination for Monolayers 46
Microstructural Evolution in Thick Film Growth 50
3.6 Future Prospects 53
INFRARED SPECTROSCOPY IN THE CHARACTERIZATION OF ORGANIC THIN FILMS 57
4.1 Introduction 57
Specific Needs for Characterizing Organic Thin Films 58
General Principles and Capabilities of Infrared Spectroscopy for Surface and Thin Film Analysis 59
4.2 Quantitative Aspects 64
Spectroscopic Intensities 64
Electromagnetic Fields in Thin Film Structures 65
4.3 The Infrared Spectroscopic Experiment 71
General Instrumentation 71
Experimental Modes 71
Additional Aspects 80
4.4 Examples of Applications 81
Self-Assembled Monolayers on Gold by External Reflection 81
Octadecylsiloxane Monolayers on SiO2 by Transmission 82
Langmuir-Blodgett Films on Nonmetallic Substrates by External Reflection 83
RAMAN SPECTROSCOPIC CHARACTERIZATION OF ORGANIC THIN FILMS 87
5.1 Introduction 87
5.2 Fundamentals of Raman Spectroscopy 88
5.3 Instrumental Considerations 90
5.4 Raman Spectroscopic Approaches for the Characterization of Organic Thin Films 92
Integrated Optical Waveguide Raman Spectroscopy(IOWRS) 92
Total Internal Reflection Raman Spectroscopy 94
Surface Enhanced Raman Scattering 95
Normal Raman Spectroscopy 96
Resonance Raman Spectroscopy 97
Plasmon Surface Polariton Enhanced Raman Spectroscopy 97
Fourier Transform Raman Spectroscopy 98
Waveguide Surface Coherent Anti-Stokes Raman Spectroscopy(WSCARS) 99
5.5 Selected Examples of Thin Film Analyses 99
Raman Spectral Characterization of Langmuir-Blodgett Layers of Arachidate and Stearate Salts 99
Raman Spectral Characterization of Self-Assembled Monolayers of Alkanethiols on Metals 104
Surface Enhanced Resonance Raman Spectral Characterization of Langmuir-Blodgett Layers of Phthalocyanines 107
5.6 Prospects for Raman Spectroscopic Characterization of Thin Films 110
SURFACE POTENTIAL 113
6.1 Introduction 113
6.2 Origins of the Contact Potential Difference and Surface Potential 114
The Work Function 114
Contact Potential Difference and Surface Potential 115
Surface Potential Changes Induced by Adsorbates 116
6.3 Measurement of Surface Potential 117
Capacitance Techniques 117
Ionizing-Probe Technique 119
6.4 Surface Potentials of Organic Thin Films 121
Air-Water Interface:Surface Potential of Langmuir Monolayers 121
Air-Solid Interface:Surface Potential of L-B and Related Films 124
6.5 Conclusions 129
X-RAY DIFFRACTION 133
7.1 Introduction 133
7.2 Basic Principles 134
7.3 Structure Normal to Film Plane 135
7.4 Structure Within the Film Plane 139
7.5 Summary 145
HIGH RESOLUTION EELS STUDIES OF ORGANIC THIN FILMS AND SURFACES 147
8.1 Introduction 147
8.2 The Scattering Mechanism 148
Dipole Scattering 149
Impact Scattering 149
Resonance Scattering 150
8.3 The Spectrometer 151
8.4 EELS Versus Other Techniques:Advantages and Disadvantages 153
8.5 Examples 153
Resolution Enhancement 153
Linearity 155
Depth Sensitivity 157
Molecular Orientation 159
Local Versus Long-Range Interactions 160
Surface Segregation 161
8.6 Conclusions 162
WETTING 165
9.1 Introduction 165
9.2 Contact Angles 166
9.3 Techniques for Contact Angle Measurements 171
Axisymmetric Drop Shape Analysis-Profile(ADSA-P) 171
Axisymmetric Drop Shape Analysis-Contact Diameter(ADSA-CD) 173
Capillary Rise Technique 175
9.4 Phase Rule for Moderately Curved Surface Systems 175
9.5 Equation of State for Interfacial Tensions of Solid—Liquid Systems 179
9.6 Drop Size Dependence of Contact Angle and Line Tension 182
9.7 Contact Angles in the Presence of a Thin Liquid Film 184
9.8 Effects of Elastic Liquid-Vapor Interfaces on Wetting 187
SECONDARY ION MASS SPECTROMETRY AS APPLIED TO THIN ORGANIC AND POLYMERIC FILMS 193
10.1 Introduction and Background 193
Overview of the SIMS Method and Experiment 193
Ion Formation Mechanisms 196
Comparisons to Other Surface Analysis Techniques 196
The Motivation for Thin Organic Films as Model Systems 196
10.2 Qualitative Information:Mechanisms of Secondary Molecular Ion Formation 197
Structure-Ion Formation Relationships 197
Applications to Self-Assembled Film Chemistry 199
10.3 The Study of Sampling Depth in the SIMS Experiment 200
10.4 Quantitation in SIMS 203
Development of Quantitation Methods 203
Application of Quantitative Schemes to Thin Film Chemistry 205
10.5 Imaging Applications 208
10.6 Summary and Prospects 208
X-RAY PHOTOELECTRON SPECTROSCOPY OF ORGANIC THIN FILMS 213
11.1 Introduction 213
11.2 Experimental Considerations 214
11.3 Binding Energy Shifts 215
11.4 XPS of Molten Films 215
11.5 Angular Dependent XPS 216
11.6 ETOA XPS of Self-Assembled Monolayers 218
11.7 Conclusions 223
MOLECULAR ORIENTATION IN THIN FILMS AS PROBED BY OPTICAL SECOND HARMONIC GENERATION 227
12.1 Introduction 227
12.2 Experimental Considerations 228
12.3 Molecular Nonlinear Polarizability Calculation 232
12.4 Measurements of the Surface Nonlinear Susceptibility 236
12.5 Molecular Orientation Calculation 239
Case 1:βZZZ only 240
Case 2:βZXX only 241
Case 3:βXXZ(=βXZX)only 241
Case 4:βZZZ and βZXX 241
Case 5:βZXX and βXXZ(=βXZX) 242
12.6 Absolute Molecular Orientation Measurements 243
12.7 Summary and Conclusions 244
APPENDIX:TECHNIQUE SUMMARIES 251
1 Auger Electron Spectroscopy(AES) 251
2 Dynamic Secondary Ion Mass Spectrometry(Dynamic SIMS) 252
3 Fourier Transform Infrared Spectroscopy(FTIR) 253
4 High-Resolution Electron Energy Loss Spectroscopy(HREELS) 254
5 Low-Energy Electron Diffraction(LEED) 255
6 Raman Spectroscopy 256
7 Scanning Electron Microscopy(SEM) 257
8 Scanning Tunneling Microscopy(STM)and Scanning Force Microscopy(SFM) 258
9 Static Secondary Ion Mass Spectrometry(Static SIMS) 259
10 Transmission Electron Microscopy(TEM) 260
11 Variable-Angle Spectroscopic Ellipsometry(VASE) 261
12 X-Ray Diffraction XRD) 262
13 X-Ray Fluorescence(XRF) 263
14 X-Ray Photoelectron Spectroscopy(XPS) 264
Index 265