76. Photoemission Electron Microscope

PEEM is one of the imaging type photoelectron microscopy (Kinoshita et al. in J Phys Soc Jpn 82 2013 [1]). The apparatus is equipped with some electrostatic lens systems, a microchannel plate (MCP) and a fluorescent screen. When excitation photons are injected onto a sample, photoelectrons including secondary electrons are emitted. The lens systems magnify and focus the images of spatial distributions of these electrons from the sample onto the MCP. Then the screen is illuminated by these amplified electrons. By using a charge coupled device (CCD) camera, a magnified image of the emitted electron distributions from the sample surface can be obtained. When a mercury lamp or a deuterium lamp is used as an excitation source, the distribution of the local work function of the surface becomes visible, since the photon energy is about 4 eV.