X-ray photoelectron spectroscopy (XPS),  also knwon as Electron Spectroscopy for Chemical Analysis (ESCA), is a widely used technique for obtaining chemical information of  various material surfaces.  Core-level electrons are emitted from a surface after it has been irradiated with soft X-ray. The low kinetic energy (0 - 1500 eV) of emitted photoelectrons limit the depth from which it can emerge so that XPS is a very surface-sensitive technique and the sample depth is in the range of few nanometers. Photoelectrons are collected and analysed by the instrument to produce a spectrum of emission intensity versue electron binding energy.  In general, the binding energies of the photoelectrons are characteristic of the element from which they are emanated so that the spectra can be used for surface elemental ananlysis. Small shifts in the elemental binding energies provide information about the chemical state of the elements on the surface. Therefore, the high resolution XPS studies can provide the chemical state information of the surface.
 

Typical Analytical Applications

• Elemental Analysis : Atomic abundance of all elements (except H and He) on metals, insulators, powders, etc
• Chemical state information (e.g. identification oxidation state)
• Quantitative analysisa

Examples of Applications:

• Chemical Analysis of Metal Alloy
  
• XPS of CNTs
  

Instrument Specification

• SKL-12 spectrometer modified with VG CLAM 4 multichannel hemispherical analyser
• Twin anode (Al/Mg) X-ray sources (no monochrometer)
• 5 keV Argon ion gun for sample cleaning
• UV lamp for UPS analysis

Limitation

• Samples must be solid and vacuum compatible
• Sample size : 6mm to 20mm in diameter

For further enquiry, please contact Mr. Benson Leung, Tel: (852) 34115876, email scleung@hkbu.edu.hk