Electron beam induced desorption

Another advantage of AES is the speed of the analysis. Cylindrical mirror analysers possess the ability to examine the complete Auger spectrum in less than a second and rapid data acquisition may be critically important in kinetic studies. This very high-speed analysis is most important in the presence of electron beam induced desorption and damages, which are one of the major drawbacks of AES. 

The second application is to the direct measurement of adsorption-desorption processes using the Auger peak height of the particular element as a monitor. The principal limitation is the possible influence of the electron beam on the adsorbate, which can result in beam-induced desorption, adsorption or dissociation. The basis of electron-stimulated desorption (ESD) was established some time ago independently be Menzel and Gomer [38] and Redhead [39]. Electron impact causes Franck—Condon transitions of bound electrons in the adsorbed species into excited states. There is, therefore, a probability of dissociation with subsequent desorption of the particular species involved. As an example of these effects on semiconductor surfaces, Joyce and Neave [40] have reported results on silicon, while Ranke and Jacobi [41] have discussed the electron-stimulated oxidation of GaAs. 

Madey T E ef a/1993 Structure and kinetics of electron beam damage in a chemisorbed monolayer PFjOn Ru(OOOI) Desorption Induced by Electronic Transitions DIET V vol 31, ed A R Burns, E B Stechel and D R Jennison (Berlin Springer)... 

Another novel method described recently involves the use of the electron-stimulated desorption (ESD, EID) of species from a surface. Lichtmann and Campuzano [239] used a scanning electron beam to induce desorption of F+ ions from a fluoridised molecule and obtained traces of F+ current (measured in a mass spectrometer) versus distance scanned across the sample. Only qualitative results were obtained but this again illustrates the strength of the scanning technique for boundary diffusion studies. 

Electron beam impact can induce the desorption of molecules—neutral or ionized—in the direction of their chemical bond to the surface. The technique that takes advantage of this phenomenon to learn about surface bond directionality is called electron-stimulated desorption ion-angular distribution (ESDIAD) [56, 61, 64, 79-83]. Describe the bonding of a polyatomic molecule on a transition metal surface as determined by ESDIAD [112]. 

Electron-beam incidence induces the desorption of adsorbed molecules either as neutral or as ionized species [114-116]. Discuss the mechanisms of this process, and indicate the structural information that can be obtained and the cross sections for the desorption processes. 

The low-energy cluster beam deposition setup at the Universitat Karlsruhe consists of three differential pumping stages as shown in Figure 3.20. Their source produces ions through electron impact induced ionization/desorption of powder in a... 

D. H. Buckley Both elements of the polymer structure are present on the solid surface in the proper intensities ratios. It is only when the electron beam energy is appreciably increased that fluorine induced desorption occurs. 

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