Principles and Practice of Variable Pressure / Environmental Scanning Electron Microscopy (VP-ESEM)

• Offers a simple starting point to VPSEM, especially for new users, technicians and students containing clear, concise explanations
• Crucially, the principles and applications outlined in this book are completely generic: i.e. applicable to all types of VPSEM, irrespective of manufacturer.
• Information presented will enable reader to turn principles into practice
• Published in association with the Royal Microscopical Society (RMS) -www.rms.org.uk

Von ausführlichen Literaturhinweisen über die technischen Voraussetzungen der Rasterelektronentunnelmikroskopie geht der Text zur Beschreibung der Objektvorbereitung über. Die Kapitel im Hauptteil behandeln das Thema aus jeweils verschiedenen Fachgebieten: Physik, Materialwissenschaft, Biowissenschaften, industrielle Produktion von Lebensmitteln oder Kosmetika. Auch interdisziplinäre Ansätze werden beleuchtet.

Contents

Chapter 1 -A brief historical overview

1.1 Scanning electron microscopy

1.2 The development of imaging in a gas environment

Chapter 2 -Principles of SEM

2.1 Introduction

2.2 Electron sources

2.3 Electron optics

2.4 Signals and detection

2.5 Practical aspects of electron beam irradiation

2.6 the sem in operation

Chapter 3 -General principles of VP-ESEM: utilising a gas

3.1 Introduction

3.2 VP-ESEM instrumentation

3.3 Signal generation in a gas

3.4 Imaging with water vapour

Chapter 4 -Imaging and analysis in the VP-ESEM: the influence of a gas

4.1 Introduction

4.2 Background to theoretical calculations

4.3 Which gas?

4.4 Exploring the gas path length

4.5 How much gas?

4.6 X-ray microanalysis in the VP-ESEM

Chapter 5 -Imaging uncoated specimens in the VP-ESEM

5.1 Introduction

5.2 Electronic structure

5.3 Factors affecting secondary electron emission

5.4 The influence of the specimen on the system

5.5 Time- and temperature-dependent effects

5.6 imaging soft materials

5.7 Effects of ions on imaging

5.8 Imaging with a gas: summary

Chapter 6 -A lab in a chamber – in situ methods in VP-ESEM and other applications

6.1 Introduction

6.2 Nanocharacterisation of insulating materials

6.3 In situ experiments

6.4 Other applications

Dr Debbie Stokes, Academic Visitor, Cavendish Laboratory, University of Cambridge, UK and Director of MicroSci; Obtained her degree in polymers from Bristol University in 1994.
In 1996 moved to Cavendish laboratory to do her Ph D on use of environmental SEM with Professor Athene Donald.
In 1999 became Royal Society Dorothy Hodgkin Research Fellow and a Junior Research Fellow of Newnham College, Cambridge, becoming a Senior Research Fellow in 2002.
Currently working at the Cavendish Laboratory funded by her consultancy business MicroSci.

Scanning electron microscopy (SEM) is a technique of major importance and is widely used throughout the scientific and technological communities. The modern SEM is capable of resolution on the order of a few Angstroms (i.e. sub-nanometer), subject to the limits of electron-specimen interactions. However, for a long time it has been apparent that the high vacuum SEM needed to develop in respects other than increased resolution. Hence the advent of SEMs that utilise a gas for image formation while simultaneously providing charge stabilisation for electrically non-conductive specimens and/or a suitable environment for materials and experiments involving water.

This text outlines the principles and applications in a generic way, applicable to readers familiar with any of the types of VP-ESEM on the market, irrespective of manufacturer

The book addresses various aspects of the topic in six chapters.

• Chapter 1 - A brief historical overview contains background information charting the development and growth of the technique and its underlying principles

• Chapter 2 - Principles of SEM gives an overview of various aspects of the conventional high vacuum SEM, in preparation for later chapters covering the greater variety of operating conditions associated with the VP-ESEM

• Chapter 3 - General principles of VP-ESEM: utilising a gas reviews the basic scientific principles of signal formation and collection in a gaseous environment, including specimen stability as a function of water vapour pressure and/or temperature.

• Chapter 4 - Imaging and analysis in the VP-ESEM: the influence of a gas looks at the properties and effects of different gases, pressures and primary electron energies, with particular attention to electron scattering and its effects on imaging and microanalysis

• Chapter 5 - Imaging uncoated specimens in the VP-ESEM briefly looks at the pros and cons of putting native-state materials in the VP-ESEM, such as primary electron beam penetration, radiation damage and, crucially, the properties of materials in an electric field and the influence of gaseous positive ions

• Chapter 6 - A lab in a chamber – in situ methods in VP-ESEM and other applications concludes the book with a survey of dynamic experiments such as: tensile testing, vapour-deposition of nanostructures, oxidation and reduction,lithography, ice crystallization and wetting of surfaces, to name a few, as well as unique imaging methods, plus an extensive review of the literature covering both hard and soft materials.

This book is intended as a guide to help those that are just starting out with VP-ESEM, as well as those with more experience looking to gain a deeper appreciation of the concepts.