Surface Imaging Using Electrons Excited by Metastable-Atom Impacts

This article introduces our recent study on solid surfaces by metastable electron emission microscopy (MEEM) which is in principle selectively sensitive to outermost-surface electronic states. Examples of surface images by MEEM are shown for a SiO2 pattern on Si(100) and a microstructured thin film of organic semiconductor, chloroaluminum phthalocyanine (ClAlPc), on a MoS2 surface. The latter result demonstrates that very large organic molecule can diffuse on the surface. For the ClAlPc film, the results obtained by photoemission electron microscopy (PEEM) using photons near the threshold ionization energy of the target are also shown.