Multitechnique Applications
Sometimes the analyst must supplement XPS with other techniques. ESCALAB 250 and Sigma Probe can be used to produce data from Auger electron spectroscopy (AES), ultra violet photoelectron spectroscopy (UPS) and ion scattering spectroscopy (ISS). All these techniques can be used with the sample in the same position. With the Multilab all these techniques (and more) can be incorporated as standard.
Auger Electron Spectroscopy (AES)
The field emission electron gun, the FEG 1000, which may be fitted to both the ESCALAB 250 and Sigma Probe, is capable of high current at small spot size and therefore can produce scanning Auger maps (SAM) and spectra at very high spatial resolution.
This example is a copper/nickel alloy. The SEM image (left) shows a number of small corrosion pits. The SAM image (right) shows the chlorine distribution in red and the copper distribution in green. A comparison of the two images shows that the chlorine is associated with the corrosion pits. The spatial resolution in these images is ~100nm.
The spectra were acquired from both the corroded (red) and the non-corroded (blue) areas. The analysis positions were defined using the image.
Ion Scattering Spectroscopy (ISS)
All of the lens and analyser electronics on both the ESCALAB 250 and Sigma Probe have reversible polarity. The instrument is therefore able to acquire ISS spectra using the EX05 ion gun which is fitted to the instrument.
ISS is the technique of choice when an analysis of only the top monolayer is required.
The examples shown here are from a phosphor bronze, one example uses helium ions to produce a wide mass range spectrum while the other uses argon ions to separate the isotopes of copper in the bronze.
Ultra Violet Photoelectron Spectroscopy (UPS)
UPS is a technique which may be added to ESCALAB 250 or Sigma Probe . The UV lamp used on the instruments can be operated to produce either He I or He II radiation.
This example compares the UPS spectrum from Dy under He I and He II. |
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