Noncontact Atomic Force Microscopy

1 Introduction.- 1.1 AFM in Retrospective.- 1.2 Present Status of NC-AFM.- 1.3 Future Prospects for NC-AFM.- References.- 2 Principle of NC-AFM.- 2.1 Basics.- 2.1.1 Relation to the Scanning Tunneling Microscope (STM).- 2.1.2 Atomic Force Microscope (AFM).- 2.1.3 Operating Modes of AFMs.- 2.1.4 Scanning Speed, Signal Bandwidth and Noise.- 2.2 The Four Additional Challenges Faced by AFM.- 2.2.1 Jump-to-Contact and Other Instabilities.- 2.2.2 Contribution of Long-Range Forces.- 2.2.3 Noise in the Imaging Signal.- 2.2.4 Non-Monotonic Imaging Signal.- 2.3 Frequency-Modulation AFM (FM-AFM).- 2.3.1 Experimental Setup.- 2.3.2 Applications.- 2.4 Relation between Frequency Shift and Forces.- 2.4.1 Generic Calculation.- 2.4.2 Frequency Shift for a Typical Tip—Sample Force.- 2.4.3 Calculation of the Tunneling Current for Oscillating Tips.- 2.5 Noise in Frequency-Modulation AFM.- 2.5.1 Generic Calculation.- 2.5.2 Noise in the Frequency Measurement.- 2.5.3 Optimal Amplitude for Minimal Vertical Noise.- 2.6 A Novel Force Sensor Based on a Quartz Tuning Fork.- 2.6.1 Quartz Versus Silicon as a Cantilever Material.- 2.6.2 Benefits in Clamping One of the Beams (qPlus Configuration).- 2.7 Conclusion and Outlook.- References.- 3 Semiconductor Surfaces.- 3.1 Instrumentation.- 3.2 Three-Dimensional Mapping of Atomic Force.- 3.3 Control of Atomic Force.- 3.4 Imaging Mechanisms for Si(100)2?l and Si(100)2?l:H.- 3.5 Surface Strain on an Atomic Scale.- 3.6 Low Temperature Image of Si(100) Clean Surface.- 3.7 Mechanical Control of Atom Position.- 3.8 Atom Identification Using Covalent Bonding Force.- 3.9 Charge Imaging with Atomic Resolution.- 3.10 Mechanical Atom Manipulation.- References.- 4 Bias Dependence of NC-AFM Images and Tunneling Current Variations on Semiconductor Surfaces.- 4.1 Experimental Conditions.- 4.2 Bias Dependence of NC-AFM Images for Si(lll)7?7.- 4.2.1 Mechanism of Inverted Atomic Corrugation.- 4.2.2 NC-AFM Imaging and Tunneling Current.- 4.3 NC-AFM Images for Ge/Si(lll).- 4.4 Concluding Remarks.- References.- 5 Alkali Halides.- 5.1 Introduction.- 5.1.1 Experimental Techniques.- 5.1.2 Relevant Forces.- 5.2 Imaging of Single Crystals.- 5.2.1 Sample Preparation.- 5.2.2 Atomic Corrugation.- 5.2.3 Imaging of Defects.- 5.2.4 Mixed Alkali Halide Crystals.- 5.3 Imaging of Thin Films.- 5.3.1 Preparation of Thin Films.- 5.3.2 Atomic Resolution at Low-Coordinated Sites.- 5.4 Radiation Damage.- 5.4.1 Metallization and Bubble Formation in CaF2.- 5.4.2 Monatomic Pits in KBr.- 5.5 Dissipation Measurements.- 5.5.1 Material and Site-Specific Contrast.- 5.5.2 Using Damping for Distance Control.- References.- 6 Atomic Resolution Imaging on Fluorides.- 6.1 Experimental Techniques.- 6.2 Tip Instabilities.- 6.3 Flat Surfaces.- 6.4 Step Edges.- References.- 7 Atomically Resolved Imaging of a NiO(001) Surface.- 7.1 Antiferromagnetic Nickel Oxide.- 7.2 Experimental Considerations.- 7.3 Morphology of the Cleaved Surface.- 7.4 Atomically Resolved Imaging Using Non-Coated and Fe-Coated Si Tips.- 7.5 Short-Range Magnetic Interaction.- 7.6 Analysis of the Cross-Section.- 7.7 Conclusion.- References.- 8 Atomic Structure, Order and Disorder on High Temperature Reconstructed ?-Al2O3(0001).- 8.1 The Clean Surface.- 8.2 Defect Formation upon Water Exposure.- 8.3 Self-Organized Formation of Nanoclusters.- References.- 9 NC-AFM Imaging of Surface Reconstructions and Metal Growth on Oxides.- 9.1 Introduction.- 9.2 l?l to 1?3 Phase Transition of TiO2(100).- 9.3 Surface Reconstructions of TiO2(110).- 9.4 The 1?2 Reconstruction of SnO2(110).- 9.5 Imaging Thin Film Alumina: NiAl(110)-Al2O3.- 9.6 Growth of Cu and Pd on $$ \alpha - Al_2 O_3 \left( {0001} \right) - \sqrt {31} \times \sqrt {31} R \pm 9^\circ
$$.- 9.7 A Short-Range-Ordered Overlayer of K on TiO2(110).- 9.8 Conclusions.- References.- 10 Atoms and Molecules on TiO2(110) and CeO2(111) Surfaces.- 10.1 Background.- 10.2 Brief Description of Experiments.- 10.3 Surface Structures of TiO2(110).- 10.4 Adsorbed Atoms and Molecules on TiO2(110).- 10.4.1 Carboxylate Ions on TiO2(110).- 10.4.2 Hydrogen Adatoms on TiO2(110).- 10.5 Fluctuation of Acetate Ions on TiO2(110).- 10.6 Surface Structures of CeO2(111).- 10.7 Conclusions.- References.- 11 NC-AFM Imaging of Adsorbed Molecules.- 11.1 Nucleic Acid Bases on a Graphite Surface.- 11.2 Double-Stranded DNA on a Mica Surface.- 11.3 Alkanethiol on a Au(111) Surface.- References.- 12 Organic Molecular Films.- 12.1 AFM Imaging of Molecular Films.- 12.1.1 Fullerenes.- 12.1.2 Alkanethiol SAMs.- 12.1.3 Ferroelectric Molecular Films.- 12.2 Surface Potential Measurements.- 12.3 Technical Developments in NC-AFM Imaging of Molecules.- 12.4 Concluding Remarks.- References.- 13 Single-Molecule Analysis.- 13.1 Introduction.- 13.2 Molecules and Surface.- 13.3 Experimental Methods.- 13.4 Alkyl-Substituted Carboxylates.- 13.5 Numerical Simulation of Propiolate Topography.- 13.5.1 Sphere—Substrate Force.- 13.5.2 Sphere—Carboxylate Force.- 13.5.3 Cluster—Substrate Force.- 13.5.4 Cluster—Carboxylate Force.- 13.5.5 Simulated Topography.- 13.6 Fluorine-Substituted Acetates.- 13.7 Conclusions and Perspectives.- References.- 14 Low-Temperature Measurements: Principles, Instrumentation, and Application.- 14.1 Introduction.- 14.2 Microscope Operation at Low Temperatures.- 14.2.1 Drift.- 14.2.2 Noise.- 14.3 Instrumentation.- 14.4 Van der Waals Surfaces.- 14.4.1 HOPG(0001).- 14.4.2 Xenon.- 14.5 Nickel Oxide.- 14.6 Semiconductors.- 14.6.1 ??(z) Curves on Specific Atomic Sites.- 14.6.2 Tip-Dependent Atomic Scale Contrast.- 14.6.3 Tip-Induced Relaxation.- 14.7 Magnetic Force Microscopy at Low Temperatures.- 14.7.1 MFM Data Acquisition.- 14.7.2 Domain Structure of La0.7Ca0.3MnO3??.- 14.7.3 Vortices on YBa2Cu3O7??.- 14.8 Conclusions.- References.- 15 Theory of Non-Contact Atomic Force Microscopy.- 15.1 Introduction.- 15.2 Cantilever Dynamics.- 15.3 Theoretical Simulation of NC-AFM Images.- 15.4 Non-Contact Atomic Force Microscopy Images of Dynamic Surfaces.- 15.5 Effect of Tip on Image for the Si(100)2?l:H Surface.- 15.6 Effect of Tip on Surface Structure Change and its Relation to Dissipation.- 15.7 Conclusion and Outlook.- References.- 16 Chemical Interaction in NC-AFM on Semiconductor Surfaces.- 16.1 Introduction.- 16.2 First-Principles Calculation of Tip—Surface Chemical Interaction.- 16.3 Simulation of NC-AFM Images.- 16.4 Simulations on Various Surfaces.- 16.5 Tip-Induced Surface Relaxation on the GaAs(110) Surface.- 16.5.1 Vertical Scan Over an As Atom.- 16.5.2 Vertical Scan Over a Ga Atom.- 16.5.3 Relevance to Near-Contact STM Observations.- 16.5.4 Tip-Induced Surface Atomic Processes and Energy Dissipation in NC-AFM.- 16.6 Image Contrast on GaAs(110) for a Pure Si Tip: Distance Dependence.- 16.7 Effect of Tip Morphology on NC-AFM Images.- 16.7.1 Image Contrast for the Ga/Si Tip.- 16.7.2 Image Contrast for the As/Si Tip.- 16.8 Conclusion.- References.- 17 Contrast Mechanisms on Insulating Surfaces.- 17.1 Introduction.- 17.2 Model of AFM and Main Forces.- 17.2.1 Tip—Surface Setup.- 17.2.2 Forces.- 17.3 Simulating Scanning.- 17.3.1 The Surface.- 17.3.2 The Tip.- 17.3.3 Tip—Surface Interaction.- 17.3.4 Modelling Oscillations.- 17.3.5 Generating a Theoretical Surface Image.- 17.4 Applications.- 17.4.1 The Calcium Fluoride (111) Surface.- 17.4.2 Calcite: Surface Deformations During Scanning.- 17.5 Studying Surface and Defect Properties.- 17.6 Conclusions.- References.- 18 Analysis of Microscopy and Spectroscopy Experiments.- 18.1 Introduction.- 18.2 Basic Principles.- 18.2.1 Experimental Setup.- 18.2.2 Origin of the Frequency Shift.- 18.2.3 Calculation of the Frequency Shift.- 18.2.4 Frequency Shift for Conservative Tip—Sample Forces.- 18.3 Simulation of NC-AFM Images.- 18.3.1 Experimental NC-AFM Images of van der Waals Surfaces.- 18.3.2 Basic Principles of the Simulation Method.- 18.3.3 Applications of the Simulation Method.- 18.4 Dynamic Force Spectroscopy.- 18.4.1 Determining Forces from Frequencies.- 18.4.2 Analysis of Tip—Sample Interaction Forces.- 18.5 Conclusion.- References.- 19 Theory of Energy Dissipation into Surface Vibrations.- 19.1 Introduction.- 19.2 Possible Dissipation Mechanisms.- 19.2.1 Adhesion Hysteresis.- 19.2.2 Stochastic Dissipation.- 19.2.3 Other Mechanisms.- 19.3 Brownian Particle Mechanism of Energy Dissipation.- 19.3.1 Brownian Particle.- 19.3.2 Fluctuation—Dissipation Theorem.- 19.3.3 Oscillating Tip as a Brownian Particle.- 19.3.4 Energy Dissipated Per Oscillation Cycle.- 19.4 Nonequilibrium Considerations for NC-AFM Systems.- 19.4.1 Preliminary Remarks.- 19.4.2 Mixed Quantum—Classical Representation.- 19.4.3 Equation of Motion for the Tip.- 19.5 Estimation of Dissipation Energies in NC-AFM.- 19.6 Comparison with STM.- 19.7 Conclusions and Future Directions.- References.- 20 Measurement of Dissipation Induced by Tip—Sample Interactions.- 20.1 Introduction.- 20.2 Experimental Aspects of Energy Dissipation.- 20.3 Experimental Methods.- 20.4 Apparent Energy Dissipation.- 20.5 Velocity-Dependent Dissipation.- 20.5.1 Electric-Field-Mediated Joule Dissipation.- 20.5.2 Magnetic-Field-Mediated Joule Dissipation.- 20.5.3 Magnetic-Field-Mediated Dissipation.- 20.5.4 Brownian Dissipation.- 20.6 Hysteresis-Related Dissipation.- 20.6.1 Magnetic-Field-Induced Hysteresis.- 20.6.2 Hysteresis Due to Adhesion.- 20.6.3 Hysteresis Due to Atomic Instabilities.- 20.7 Dissipation Imaging with Atomic Resolution.- 20.8 Dissipation Spectroscopy.- 20.9 Conclusion.- References.