How do I analyze XPS peaks?

How to Analyze XPS Spectra Data

1. XPS analysis is rooted in understanding the position and intensity of peaks on the survey scans and the high-resolution spectra data.
2. The binding energy is calculated from the difference in the energy of the x-ray source and the kinetic energy of the photoelectron being detected.

How do I fit an XPS file?

To fit an XPS spectra I typically do the following steps:

1. Smooth the curve.
2. Subtract the baseline (shirley background)
3. Figure out the peak positions and FWHM from the literature.
4. See if the peak shows multiplet or spin-orbital splitting.

What pressure is best when performing XPS?

XPS requires high vacuum (residual gas pressure p ~ 10−6 Pa) or ultra-high vacuum (p < 10−7 Pa) conditions, although a current area of development is ambient-pressure XPS, in which samples are analyzed at pressures of a few tens of millibar.

Where can I find XPS peak?

First divide by the X-ray flux if you have used different X-ray energies for different spectra (more X-rays will give higher intensity XPS peaks). Then divide by the photoionization cross-section for the core level you’re looking at it.

What is the principle of XPS?

Photoemission principle: When an x-ray (red arrow) bombards a sample (left), some electrons (yellow spheres) become excited enough to escape the atom (right). XPS is conducted in ultrahigh vacuum (UHV) conditions, around 10-9 millibar (mbar).

Why do we use XPS?

X-ray Photoelectron Spectroscopy (XPS) also known as Electron Spectroscopy for Chemical Analysis (ESCA) is the most widely used surface analysis technique because it can be applied to a broad range of materials and provides valuable quantitative and chemical state information from the surface of the material being …

Is XPS destructive?

​XPS is a non-destructive technique to measure surface chemistry of solid materials, in particular the chemical composition and electronic state.

How do I quantify XPS data?

XPS spectra are, for the most part, quantified in terms of peak intensities and peak positions. The peak intensities measure how much of a material is at the surface, while the peak positions indicate the elemental and chemical composition.

What is binding energy in XPS?

X-ray photoelectron spectroscopy (XPS) is a surface analytical technique, which is based upon the photoelectric effect. Each atom in the surface has core electron with the characteristic binding energy that is conceptually, not strictly, equal to the ionization energy of that electron.

Why do we need curve fitting in XPS?

Curve/peak fitting is often the only way to extract quantitative information from these spectra. The objective of curve-fitting high-resolution core XPS spectra with a set of component peaks is to separate the photoemission signal originating from distinct elemental or chemical states.

How can I do peak fitting my XPS spectra?

* The spectra you show are smoothed curves. Do not peak fit the smoothed curves. Peak fit to the unsmoothed raw (noisy) data. * You will want to remove the background properly. The best to use is a Shirley or Tougaard shape. The best method is to remove the background as part of the peak fitting process rather than before it.

How are XPS and Auger peak positions quantified?

Figure 1: XPS and Auger peaks appear above a background of scattered electrons. XPS spectra are, for the most part, quantified in terms of peak intensities and peak positions. The peak intensities measure how much of a material is at the surface, while the peak positions indicate the elemental and chemical composition.

How are peaks represented in a curve fitting spectra?

Although the details of curve fitting depend on the techni- que in question, the curve fitted spectra generally contain overlapping peaks. Each of these peaks is represented by a function that reflects the physical process involved in generating the original signal. XPS data interpretation and representation range from a