High-performance GaAs polarized electron source for use in inverse photoemission spectroscopy

The design and operating properties of a GaAs polarized electron source are presented. An electron optical system is described that passes more than 80% of the emitted electrons at 10 μA to the target under low-energy (7–20 eV) parallel beam conditions. Laser excitation can give rise to abnormal energy distributions of the photoemitted electron beam. The existence of longitudinal modes gives a possible explanation for this behavior, which can be avoided using a mode stabilized light source. The overall performance of the polarized electron source is demonstrated by inverse photoemission spectra from Ni(110).