Surface and Interface Analysis

Auteur

Seong H. Kim, PhD, is Distinguished Professor at the Department of Chemical Engineering of The Pennsylvania State University, USA. He is also affiliated with the Department of Materials Science and Engineering and the Department of Chemistry. He received his BS and MS degrees from Yonsei University, South Korea, and his PhD from Northwestern University, USA. He then worked as a postdoctoral researcher at the University of California, Berkeley, USA, before joining the faculty of chemical engineering at Penn State.

Texte du rabat

Comprehensive textbook covering characterization techniques to understand the chemistry and structure of materials on surfaces and at interfaces

Surface and Interface Analysis is a comprehensive textbook resource that covers everything readers need to know about surface energy, molecular speciation, and optical and physical characterization techniques. Assuming only basic knowledge of general chemistry (electronic orbitals, organic functional groups), physics (electromagnetic waves, Maxwell equations), physical chemistry (Schrödinger equation, harmonic oscillator), and mathematics (wave equations, covariance matrix), this textbook helps readers understand the underlying principles of the discussed characterization techniques and enables them to transform theoretical knowledge into applied skills through a Maieutic pedagogical approach.

Written by a highly qualified professor, Surface and Interface Analysis includes information on:

• Relationship between atomic and molecular orbitals and compositional analysis principles based on measurements of photoelectrons, Auger electrons, x-rays, and secondary ions emitted from the surface
• Governance of electromagnetic wave propagation in a dielectric medium and what can be learned from analyzing the electromagnetic wave reflected from the interface
• Surface metrology using light reflection (non-contact) and scanning probe (contact) and analysis of mechanical properties through indentation

• Artifacts and misinterpretations that may be encountered during analysis
  Surface and Interface Analysis is an ideal textbook resource on the subject for graduate students in the fields of solid state physics, optics, materials science, chemistry, and engineering who want to learn and apply advanced materials characterization methods, along with undergraduate students in advanced elective courses.

Contenu

SURFACE-GAS INTERACTIONS / SURFACE ENERGY

How many atoms are typically present at the surface?

Why do many surface characterization techniques work in ultra-high vacuum?

What is the relationship between the surface energy and the Gibbs free energy? Why have we not considered surface energy when we learned the Gibbs free energy in UG thermodynamics class?

Can we relate the surface energy to the bond energy of a material?

Why is a liquid droplet in free space always in the spherical shape? What determines the shape of solid nanoparticles?

How to measure the surface energy?

Will the surface energy affect the bulk property? Or it will not matter because the bulk structure is always determined by the chemical bonds in the bulk phase? If the bulk property is affected by the surface contribution, when will it happen?

X-RAY PHOTOELECTRON SPECTROSCOPY - ELEMENTAL COMPOSITION ANALYSIS

Basic principles:

What properties of a material does XPS probe? How can we identify what elements are present in the surface of a sample using XPS?

How does the binding energy of electron orbital changes with atomic number?

What orbitals can be probed using an Al K X-ray source?

How is the binding energy of the photoelectron measured?

Why are photoelectrons detected in the energy regions between two 'quantum mechanically allowed' binding energies?

What relaxation processes can occur upon / during the photoelectron emission process? Can similar relaxation process occur when the sample is bombarded with a high energy electron beam?

What other characterization techniques rely on such relaxation processes? (Auger electron spectroscopy / Energy dispersive X-ray spectroscopy)

How many peaks are expected for photoemission from a given electron orbital? If there is more than one peak, what are their relative intensities?

What determines the 'surface sensitivity' in XPS analysis? How deep can XPS probe for a given material?

Why can't we see hydrogen in XPS?

Instrumentation:

How are X-rays generated? How can we get monochromatic X-rays? Why is it important to use Monochromatic X-rays?

How is the kinetic energy of photoelectron measured? What is the reference used to measure the kinetic energy of photoelectron?

Is the Einstein's energy conservation equation sufficient to calculate the binding energy from the measured kinetic energy? Or should something else be considered?

If the sample is not conducting, then it can be charged during the XPS analysis. What problem does it cause? How can we resolve it?

Can XPS be operated in near-ambient pressure? Why would one want to do XPS analysis in near-ambient pressure conditions?

How can we detect the amount of the energy-screened photoelectrons? How can we increase the signal-to-noise ratio in the photoelectron detection?

How can we do chemical imaging with XPS?

Qualitative Analysis:

Is the binding energy of a core electron fixed or changed depending on the chemical status of the element? - initial state effects

In the case of the C 1s signal of organic compounds, what affect the binding energy of the photoelectron?

How can we distinguish the photoelectron emission from carbon in ether group vs. alcohol group? How can we expand the chemical identification capacity of C 1s XPS for various organic groups?

What governs the energy level of the valence band? What can be learned by analyzing the valence band with XPS?

In classical mechanics concept, the "final" state "after" the photoelectron emission would not affect the kinetic energy of the photoelectron. But, the photoelectron emission is a quantum mechanical process whose probability depends on the initial and final state wavefunctions. What final state effects are to be considered in analysis of transition metals?

In the case of transition metals, measuring the binding energy of the most representative peak does not always give the sufficient information to determine the oxidation state of the element. Then, what else can we do?

Quantitative Analysis

How to remove / subtract the background originating from the inelastic scattering?

What governs the peak shape and width?

When should we consider asymmetric peak shape? Why is it helpful or not helpful to consider the asymmetry in XPS peak fitting?

What are the critical factors affecting the peak intensity (=area) in XPS?

Is the relative sensitivity factor (RSP) constant for a given element?

Depth Profiling

How can we use the photoelectron escape probability for depth profiling? What is the max depth this method can be used?

For deep depth profiling, we need to use an ion sputter gun. What governs the depth resolution in sputter depth profile analysis? How to improve the depth resolution in the sputter profiling? the same is applied to secondary ion mass spectrometry (SIMS)

What are possible artifacts encountered during the sputter depth profiling?

Is XPS analysis truly non-destructive if ion sputtering is not used?

X-RAY ABSORPTION SPECTROSCOPY (XAS)

What electronic transition is probed in XAS?

What causes fine structures in X-ray absorption process?

Is XAS a surface-sensitive or bulk analysis? What is measured during the XAS analysis?

How can the orientation of molecules be determined in NEXAFS / XANES?

How can the local structure around a specific atom be determined in EXAFS?

LIGHT PROPAGATION THROUGH A MATTER & REFLECTION AT AN INTERFACE

What p…