Photoemission Microscopy

Several ways exist to image these regions of different work function. We have already discussed scanning electron and field emission microscopy in this chapter. Scanning photoemission microscopy (SPM) is carried out by scanning a focussed UV beam (beam diameter of 0.5 pm) over the surface and recording the photoemis-... 

Scanning LEED, oscillatory reactions, 39 69 Scanning photoemission microscopy, kinetic oscillations, Pt(lOO), 37 250-253 Scanning photoemission spectroscopy oscillatory reactions, 39 69... 

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. 

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... 

Fig. 27. Spatial pattern formation within a 1.5 x 1-mm2 area of a Pt( 100) surface during kinetic oscillations as recorded by scanning photoemission microscopy. (From Ref. 138.)... 

Finally, instrumentation trends today include the reduction of the analysis area to that of semiconductor device dimensions through small spot XPS and imaging photoemission microscopy. 

Ertl, Jakubith, Rotermund, v. Oertzen, Cathode Lens] Ertl, Gerhard/Sven Jaku-bith/Harm Hinrich Rotermund/Alexander v. Oertzen Imaging of Spatial Pattern Formation in an Oscillatory Surface Reaction by Scanning Photoemission Microscopy, Journal of Chemical Physics 91 (1989), p. 4942-4948. 

Another important recent development has been the introduction of high spatial resolution in photoelectron spectroscopy, in order to study lateral inhomogeneities on surfaces, chemical reaction fronts, or simply for measurements of very small samples. Two complementary approaches to photoemission microscopy have been followed. In the first, a conventional spectrometer is used while the X-ray spot is... 

Ultrafast Multiphoton Photoemission Microscopy of Solid Surfaces in Real and Reciprocal Space... 

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