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Micro-XPS using IEF and IS-PEEM
The Imaging Energy Filter (IEF), working as retarding field analyser can be used in combination with a standard FOCUS IS-PEEM. Using the built-in iris aperture of this microscope, small sample areas for spectroscopy can be selected. The
current (technical) limit of the field of view is as low as 1µm diameter. This opens up the way to do UPS- /XPS- microspectroscopy from small sample areas only depending on the photon flux available.
In the companies laboratory a 400 W monochromatized Al Ka (hn=1487 eV) source (OMICRON DAR 400 M) was used
for excitation in combination with the OMICRON XM500 monochromator.
The figures shows a wide range energy scan of a GaAs(Te) wafer with the 2p states and the corresponding Auger peaks.
With longer integration times, a more detailed insight into the spectral details of the Ga/As 3p and 3d states is given.
These spectra demonstrate, that despite of the energetic low-pass transmission characteristics of the PEEM electron
optics, a scan of a wide-range energy spectrum over as much as 1400 eV is feasible.
The spin- orbit split of 4f states of a tungsten (110) crystal is clearly resolved. FWHM of the W 4f7/2 line: 1.1 eV. The
black curve shows the DOS near the Fermi- edge.
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