Low-energy electron microscopy and spectroscopy with ESCHER: Status and prospects

We describe the layout and the capabilities of a new aberration-corrected low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) facility, which features real-and reciprocal-space spectroscopy. This new setup, named Electronic, Structural, and Chemical Nanoimaging in Real Time (ESCHER), was recently installed at Leiden University. It has three major instrumentation-related goals. First, we aim to reach the ultimate spatial resolution facilitated by aberration correction using an electron mirror, together with advanced electron detection. Second, we want to develop and exploit the spectroscopic possibilities of LEEM and PEEM in a standard laboratory environment. To this end, ESCHER is equipped with an inline energy filter and advanced photon sources. Third, we plan to extend the sample temperature range down to approximately 10 K, which is significantly lower than that achieved to date. Combined, these efforts will broaden the scientific reach of LEEM and PEEM beyond the areas of surface and materials science and into the realms of biosciences and life sciences. Here, we also present images of the first experiments performed with ESCHER focused on the growth of graphene on SiC(0001).