X- ray Photo-Emitted Electron Microscopy

 This Technique is currently not available and thus should not be included in your “Wishlist.”

X-ray PhotoEmission Electron microscopy (XPEEM) is a parallel (full-field), surface-sensitive imaging method using photo-excited electrons, and is therefore related to the photoemission process. The surface sensitivity of the technique arises from the limited inelastic mean-free path of the characteristic photoelectrons in matter. In this technique, X-ray or UV photons shine the sample surface, and an electron optical column (the PEEM) makes, with the emitted photoelectrons, a magnified image of the surface which can be further filtered in energy with an imaging spectrometer or energy filter. Depending on whether secondary electrons or true core-level electrons (both element- and bonding state-specific)  are used for microscopy, the image can be characteristic either of the work function anisotropy, or of heterogeneities in elemental distribution and chemical changes at the surface of interest. Besides imaging in real space, reciprocal space microscopy can also be performed by imaging the diffraction plane of the PEEM, which is equivalent to imaging the parallel component of the valence band photoelectron momentum. The so-called kPEEM technique is equivalent to micro-ARPES and now competes it regarding energy resolution, but is much faster since parallel, angular spectroscopic valence band imaging is performed without any sample rotation.