On space charge effects in laboratory-based photoemission electron microscopy using compact gas discharge extreme ultraviolet sources

New Journal of Physics, vol. 22, pp. 103019

Abstract

Abstract The analysis of electronic and structural properties of surfaces has been greatly advanced by photoemission electron microscopy and spectroscopy techniques. To further improve lateral and energy resolution of the instruments, it is necessary to optimize parameters of the radiation sources employed for photoemission studies (e.g. photon flux, pulse duration, spot size etc). We studied space charge effects observed in an energy-filtering photoemission electron microscope operated with a compact laboratory-scale gas-discharge extreme ultraviolet light source. In this system, we found limits of spatial- and energy-resolution controlled by the source radiation parameters. The pulse repetition rate can be varied in the kHz range and the duration of the EUV emission was measured to be several tens of nanoseconds long, and thereby very different from the standard synchrotron sources typically used for similar experiments. The spatial resolution could be improved by a factor of 5, but only on the expense of the photon density per pulse, which had to be decreased by a factor of 17 in order to reduce the image blur due to space charge effects. Furthermore, we found broadening of the x-ray photoelectron spectroscopy peaks for high photon fluxes. We have also performed a n-body Monte Carlo simulation to evaluate the difference between core-level photoelectrons and secondary electrons with respect to space charge.

Authors 6

1. Daniel W. Wilson corresponding Aachen

   RWTH Aachen University · Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

   RWTH Aachen University, Experimental Physics of EUV, 52074 Aachen, Germany

2. Christoph Schmitz

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

3. Denis Rudolf

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

4. C. Wiemann

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

5. Claus Michael Schneider

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

6. Larissa Juschkin Aachen

   RWTH Aachen University · Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Forschungszentrum Jülich, Peter Grünberg Institut, 52425 Jülich, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany

   RWTH Aachen University, Experimental Physics of EUV, 52074 Aachen, Germany