XPS Overview

X-ray Photoelectron spectroscopy (XPS) is a powerful surface analysis technique used to investigate the surface chemistry of many materials as well as to detect and monitor the changes in the surface composition with time, spatial location and depth.

The technique examines the first ~10nm of a surface and measures the elemental composition of the surface (elemental identification and quantification); the elements that contaminate the surface, if any; the chemical or electronic state of each element in the surface; the uniformity of elemental composition across the top surface (aka, line profiling or mapping); and the elemental depth profiles. XPS can provide chemical bonding information and is sensitive to all elements but Hydrogen and Helium.

XPS is routinely employed to examine inorganic compounds, metal alloys, semiconductors, polymers, pure elements, catalysts, glasses, ceramics, paints, papers, inks, woods, plant parts, make-up, teeth, bones, human implants, bio-materials, viscous oils, glues, ion modified materials and many others. Organic chemicals are not routinely analysed by XPS because they are readily degraded by either the energy of the X-rays or the heat from non-monochromatic X-ray sources.

XPS has a wide range of applications in adhesion science; aircraft; biological science; biomaterials; catalysis; chemicals; construction; corrosion science; electrical, electronics; engineering; gas, electricity and water; maritime science; metal goods; metal manufacture; metallurgy; mining; motor vehicles; paint systems; paper and printing; plastics; semiconductors; and textiles.

AES Overview

Auger Electron Spectroscopy (AES) is an analytical technique in surface chemistry and materials science that is used for determining the elemental composition of surfaces.

The technique is based on measuring the energy of electrons emitted from the surface when irradiated with electron of a specific energy; the emitted electrons having energies characteristic of the element from which they were emitted and the bonding state of those atoms. This allows for a quantitative compositional analysis of the surface of samples.

AES offers high sensitivity for all elements except Hydrogen and Helium and provides a means of monitoring the surface cleanliness of samples. Auger spectrometers allow for the investigation of the chemical environment of chemicals (chemical shift) and are more sensitive for lighter elements (where electrons are less tightly bound to the nucleus).