Photoemission Electron Microscopy PEEM

S. Kelling, S. Cerasari, H.H. Rotermund, G. Ertl, and D.A. King, A photoemission electron microscopy (PEEM) study of the effect of surface acoustic waves on catalytic CO oxidation over Pt(110), Chem. Phys. Lett. 293, 325-330 (1998). 

Scanning Tunneling Microscopy (STM) Photoemission Electron Microscopy (PEEM) Ellipsometry Microscopy for Surface Imaging (EMSI)... 

Figure 7.23 Ordering of adsorbates on a surface into islands gives rise to regions of different work function, which can be imaged because of the associated differences in photoelectron intensity. The principle forms the basis of photoemission electron microscopy (PEEM). The same principle underlies the imaging of single molecules in the field electron microscope (FEM) (see also Fig. 7.9).

NEXAFS experiments on NOM can be conducted in several modes that differ in the type of detected particle and objectives of the experiment transmission (X rays transmitted through the sample), fluorescence (fluorescent X rays due to absorption of the X-ray beam), or electron yield (photo-emitted electron) (Sparks, 2003). Alternatively, the techniques can be divided into full-field applications such as transmission X-ray microscopy (TXM) and X-ray photoemission electron microscopy (PEEM), in comparison to scanning techniques such as scanning transmission X-ray microscopy (STXM) and scanning photoemission microscopy (SPEM) that provide spatial information of elemental forms. 

Scanning tunneling microscopy (STM) Photoemission electron microscopy (PEEM)... 

Several ways exist to image these regions of different work function. SEM and FEM have been discussed earlier in this chapter. As an alternative, scanning photoemission microscopy is carried out by scanning a focused UV beam (beam diameter 0.5 pm) over the surface and recording the photoemission intensity point by point. This is of course a slow procedure, but much faster imaging in real time becomes available if the electrons are collected from the entire surface in parallel, as is carried out in photoemission electron microscopy (PEEM). The lateral resolution of this technique is presently around 200 nm, but by using... 

Abstract The controlled in-situ deposition of sexiphenyl (6P) on the (2x1) oxygen reconstruction of Cu (110) is shown to give rise to the ordered growth of large anisotropic needle-like structures on the surface. Photoemission electron microscopy (PEEM) and atomic force microscopy (AFM) results are presented for the growth of 6P (20-3) crystalline needles for a range of substrate temperatures. In addition, desorption and other interesting phenomena are discussed. 

In general, except for such idealized cases as just described, the diffusion coefficient for adsorbates will be sensitively affected by the surface structure and the coverage. Nevertheless, data derived on larger scales by macroscopic techniques (such as photoemission electron microscopy (PEEM) [42]) will be of relevance for modeling surface reactions on these scales. 

The H2 + O2 reaction on Pt(l 11), discussed in Section 6.4, had already demonstrated that a nonlinear reaction system may cause the formation of propagating concentration waves with typical length scales of >1 pm, given by the diffusion length of the adsorbates. Imaging of these features may be achieved by photoemission electron microscopy (PEEM) [14] or by optical techniques [15]. 

With the CO oxidation reaction on Pt(llO) a rich variety of concentration patterns was observed by means of photoemission electron microscopy (PEEM) with typical dimensions in the xm-range [21]. This technique is based on the different dipole moments of adsorbate complexes (Oad ad) giving rise to variations of the local work function. This in turn affects the yield of photoemitted electrons which is imaged, spatially resolved, on a fluorescent screen. 

H.H. Rotermund, Investigation of djrnamic processes in adsorbed layers by photoemission electron-microscopy (PEEM). Surf. Sci. 283(1-3), 87-100 (1993)... 

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