Сканирующая зондовая микроскопия поверхности графита и углеродосодержащих покрытий

• Автор: Вакар Зафар
• Шифр специальности: 01.04.04
• Научная степень: Кандидатская
• Год защиты: 2001
• Место защиты: Санкт-Петербург
• Количество страниц: 109 с. : ил

Introduction
Contents

Chapter 1. Scanning Tunneling and Atomic Force Microscopy
Scanning Tunneling Microscopy
1.1. Introduction
1.2. Principle of Operation
1.2.1. Metal- Metal Tunnel Contact
1.2.2. Metal-Semiconductor Tunnel Contact
1.2.3. Tunneling Current
1.3. Morphology and Atomic Structure Studies
1.4. The Current-Voltage (I-V) Characteristics
1.5. Local Density of States (LDOS) Studies
Atomic Force Microscopy
1.6 Introduction .
1.7. Principle of Operation
1.7.1 Force/Distance Relationship
1.7.2. Measuring Forces
1.7.3. Non-Modulated Methods
1.7.4. Modulation Techniques
1.7.5. Feedback Controls
1.8. Nature of Sample and Sample Surface Contamination
1.9. Cantilever and Tip
1.10. AFM Imaging Modes: (a).Contact Mode, (b) Non-Contact Mode.
(c) Tapping Mode.
Conclusions

Chapter 2. Atomic Hydrogen Interaction with Highly Oriented
Pyrolitical Graphite
2.1. Background of Hydrogen-Graphite Interaction Studies and Motivation of our
Work
2.2. Samples Preparation
2.3. STM and AFM Morphological Studies of Atomic Hydrogen Interacted-HOPG
Surface
2.4. STS Studies of Atomic Hydrogen-Interacted HOPG Surface
Conclusions
Chapter 3. Graphite layers on Ir and Re Surfaces
3.1. Graphite layers on Metals: Background and Motivation of our Work
3.2. Samples Preparation
3.2.1. Preparation of Graphite Layers on Ir(l 11) and Re(1010)
3.2.2. Intercalation of Cs Between Graphite Layer and Ir Substrate
3.3. Surface Morphology of Graphite Layer on Ir(l 11) and Re(1010)
3.4. Electronic Surface Superstructure on Graphite Layer on Ir(l 11)
Conclusions
Chapter 4. Thin Carbon Films
4.1. Carbon Films: Background and Motivation for our Work
4.2. Samples Preparation
4.3. Surface Morphology and Emission Properties of the Carbon Films
4.4. Effect of Treatments of Substrates on Characteristics of Grown Carbon Films
Conclusions

Brief Summary of the Presented Work (Conclusions)
References
Acknowledgements

voltage, causing it to oscillate. The relationship between the input oscillation and the oscillation of the probe depends on the frequency of oscillation and resonant frequency of the cantilever. Below the resonant frequency the motion of the probe is the same as the input oscillation. When frequency is increased towards the resonant condition, the probe ’whips" up and down at a higher amplitude for a given driving voltage to the piezoelectric ceramic. It also lags the input signal, called the 'phase shift'. At even higher frequencies, the phase shift can reach 180 degrees, and the amplitude will decrease to very low levels.
1.7.5. Feedback Controls
The AFM feedback circuit controls the motion of the z-piezoelectric ceramic and the z-data acquisition. There are two basic AFM feedback methods: those in which the probe is not oscillating, and those that use phase shift and/or amplitude change in oscillating cantilever systems. In feedback methods that are not based on cantilever oscillation, the sensor output is used to adjust the z-piezoelectric ceramic and generate z-data. The change in phase amplitude associated with an oscillating probe near a sample can be used to control the feedback loop in the AFM. When this is done, the cantilever is oscillated, and the oscillating photo-detector output is compared with the input oscillation through a phase-lock loop. The output is proportional to either the change in amplitude or the phase shift, which is used to control the feedback to the z-piezoelectric ceramic and to generate the z-data point. This basic concept can be used in a number of scan modes that use cantilever oscillation.
1.8. Nature of Sample and Sample Surface Contamination
The sample itself affects the probe/sample forces. Some samples are much more likely to have surface contamination than others. In addition, some samples develop a static electric charge readily. Static electricity on the sample surface can have a significant effects on the probe-sample interaction, making AFM imaging difficult [16]. The force distance relationship can also depend on the compliance of the sample surface. A surface that is soft will deform as a result of forces from the probe.