Spectromicroscopy and UPS

The imaging energy filter allows UPS with the PEEM and the HIS 13 VUV Source. The spectrum (1st derivative) resembles a typical UPS spectrum as obtained with a EA 125 hemispherical energy analyser. The peaks A and B can be attributed to non-binding O²p1) and binding Si-O states.
(* kinetic energy not corrected for analyser work function)

Equipped with the imaging energy filter, the FOCUS PEEM is capable of both microscopic and spectroscopic sample characterisation. The example shows UV-excited photoelectron spectroscopy on Pd and Si stripes (2 and 1 µm wide). Deconvolution of the spectrum obtained with the retarding field type analyser reveals a typical UPS spec-trum as can be seen from the comparison with a spectrum taken with an EA 125 hemispherical analyser.
The imaging energy filter can also be used for energy selected imaging. The spectromicroscopy images (below) obtained using NeI excitation, reveal "ring" features on the Pd/ Si stripes which were not visible with HeI photons. (The filter is not visible in the images.)

Spectromicroscopy on Pd/Si stripes measured with retarding voltages: 0-8 V, 8-10 V and 10-25 V (from the fleft). The contrast of the ring structure changes upon variation of the electron energies selected for the imaging (presumably due to an effect of the density of states).

This result has been obtained with :
FOCUS PEEM with Imaging Energy Filter
HIS 13