Nanocharacterisation

Chapter 1: Characterization of Nanomaterials using Transmission Electron Microscopy;

1.1 Introduction;

1.2 Imaging;

1.2.1 Transmission Electron Microscopy;

1.2.2 High-resolution electron Microscopy;

1.2.3 Basis of High-resolution Imaging;

1.2.4 Resolution Limits;

1.2.5 Lattice Imaging or Atomic Imaging;

1.2.6 Instrumental Parameters;

1.3 Survey of Applications;

1.3.1 Developments in HREM;

1.3.2 Small Particles and Precipitates;

1.3.3 Two-dimensional Objects;

1.3.4 One-dimensional Objects;

1.3.5 Zero-dimensional Objects;

1.3.6 Surfaces and Interfaces;

1.4 Emerging Trends and Practical Concerns;

1.4.1 Atomic Location and Quantitative Imaging;

1.4.2 Detection and Correction of Aberrations;

1.4.3 Stobbs' Factor;

1.4.4 Radiation Damage;

1.5 Conclusions;

Acknowledgements;

References;

Chapter 2: Scanning Transmission Electron Microscopy;

2.1 Introduction;

2.1.1 Basic Description;

2.1.2 Detectors;

2.1.3 Electron Energy-loss Spectroscopy;

2.2 Aberration-corrected STEM;

2.2.1 The Aberration Function;

2.2.2 Spherical and Chromatic Aberration;

2.2.3 Aberration Correctors;

2.2.4 What Do We See in a STEM?;

2.2.5 Measuring Aberrations;

2.2.6 Phonons;

2.2.7 Resolution;

2.2.8 Three-dimensional Microscopy;

2.2.9 Channeling;

2.3 Applications to Nanostructure Characterisation in Catalysis;

2.3.1 Anomalous Pt-Pt Distances in the Pt/alumina Catalytic Systems;

2.3.2 La Stabilisation of Catalytic Supports;

2.3.3 CO Oxidation by Supported Noble-metal Nanoparticles;

2.4 Summary and Outlook;

Acknowledgements;

References;

Chapter 3: Scanning Tunneling Microscopy of Surfaces and Nanostructures;

3.1 History of the STM;

3.2 The Tunneling Interaction and Basic Operating Principles of STM;

3.3 Atomic-resolution Imaging of Surface Reconstructions;

3.4 Imaging of Surface Nanostructures;

3.5 Manipulation of Adsorbed Atoms and Molecules;

3.6 Influence of the Surface Electronic States on STM Images;

3.7 Tunneling Spectroscopy;

3.8 Tip Artefacts in STM Imaging;

3.9 Conclusions;

References;

Chapter 4: Electron Energy-loss Spectroscopy and Energy Dispersive X-ray Analysis;

4.1 What is Nanoanalysis?;

4.2 Nanoanalysis in the Electron Microscope;

4.2.1 General Instrumentation;

4.3 X-ray Analysis in the TEM;

4.3.1 Basics of X-ray Analysis;

4.3.2 Analysis and Quantification of X-ray Emission Spectra;

4.3.3 Application to the Analysis of Nanometre Volumes in the S/TEM;

4.3.4 Related Photon Emission Techniques in the TEM;

4.4 Basics of EELS;

4.4.1 Instrumentation for EELS;

4.4.2 Basics of the EEL Spectrum;

4.4.3 Quantification of EELS - The Determination of Chemical Composition;

4.4.4 Determination of Electronic Structure and Bonding;

4.4.5 Application to the Analysis of Nanometre Volumes in the S/TEM;

4.5 EELS Imaging;

4.6 Radiation Damage;

4.7 Emerging Techniques;

4.8 Conclusions;

References;

Chapter 5: Electron Holography of Nanostructured Materials;

5.1.1 Basis of Off-axis Electron Holography;

5.1.2 Experimental Considerations;

5.2 The Mean Inner Potential Contribution to the Phase Shift;

5.3 Measurement of Magnetic Fields;

5.3.1 Early Experiments;

5.3.2 Experiments Involving Digital Acquisition and Analysis;

5.4 Measurement of Electrostatic Fields;

5.4.1 Electrically Biased Nanowires;

5.4.2 Dopant Potentials in Semiconductors;

5.4.3 Space-charge Layers at Grain Boundaries;

5.5 High resolution Electron Holography;

5.6 Alternative Forms of Electron Holography;

5.7 Discussion, Prospects for the Future and Conclusions;

Acknowledgements;

References;

Chapter 6: Electron Tomography;

6.1 Introduction ;

6.2 Theory of Electron Tomography;

6.2.1 From Projection to Reconstruction;

6.2.2 Backprojection: Real-space Reconstruction;

6.2.3 Constrained Reconstructions;

6.2.4 Reconstruction Resolution;

6.2.5 Measuring Reconstruction Resolution;

6.2.6 The Projection Requirement;

6.3 Acquiring Tilt Series;

6.3.1 Instrumental Considerations;

6.3.2 Specimen Support and Positioning;

6.3.3 Specimen Considerations;

6.4 Alignment of Tilt Series;

6.4.1 Alignment by Tracking of Fiducial Markers;

6.4.2 Alignment by Crosscorrelation;

6.4.3 Rotational Alignment without Fiducial Markers;

6.4.4 Other Markerless Alignment Techniques;

6.5 Visualisation, Segmentation and Data Mining;

6.5.1 Visualisation Techniques;

6.5.2 Volume Rendering;

6.5.3 Segmentation;

6.5.4 Quantitative Analysis;

6.6 Imaging Modes;

6.6.1 Bright-field TEM;

6.6.2 Dark-field (DF) Tomography;

6.6.3 HAADF STEM;

6.6.4 Meeting the Projection Requirement;

6.6.5 Experimental Considerations;

6.6.6 Limitations;

6.6.7 Core-loss (Chemical Mapping) EFTEM;

6.6.8 Low-loss EFTEM;

6.6.9 Energy Dispersive X-ray (EDX) Mapping;

6.6.10 Holographic Tomography;

6.7 New Techniques;

6.7.1 Electron Energy-loss Spectroscopy (EELS) Spectrum Imaging;

6.7.2 Confocal STEM;

6.7.3 Atomistic Tomography;

6.8 Conclusions;

References;

Chapter 7: In-situ Environmental (Scanning) Transmission Electron Microscopy;

7.1 Introduction;

7.2 Background;

7.3 Recent Advances in Atomic-resolution In-situ ETEM;

7.4 Impact of the Atomic-resolution In-situ ETEM and Global Applications;

7.5 Applications of Atomic-resolution In-situ ETEM in the Studies of Gas-Catalyst and Liquid-Catalyst Reactions;

7.5.1 Liquid-phase Hydrogenation and Polymerisation Reactions;

7.5.2 Development of Nanocatalysts for Novel Hydrogenation Chemistry and Dynamic Imaging of Desorbed Organic Products in Liquid-phase Reactions;

7.5.3 Butane Oxidation Technology;

7.5.4 In-situ Observations of Carbon Nanotubes (CNTs) in Chemical and Thermal Environments;

7.6 Conclusions;

Acknowledgements;

References;

Subject Index;