Photoemission microscopy for surface states of copper measured at different photoelectron energies

We have applied microspot photoemission spectroscopy to the surface imaging of a polycrystalline Cu plate with a lateral resolution of 0.3 mu m and an energy resolution of 30meV. The images of the crystalline islands with the (111) surface were measured by detecting photoelectrons due to the Shockley surface state (SS) and the sp-band specific to the (111) surface. The dependence of the images on the photoelectron energies was related to the mean length of the (111) terrace. The (111) island measured with the photoelectron close to the work function cutoff was found to be shifted from that measured with the Shockley state. The result demonstrates that the very high-energy resolution is essential for precise understanding of the surface images. (c) 2005 Elsevier B.V. All rights reserved.