FIM Field Ion Microscopy

Field ion microscopy (FIM), 16 503 24 74 Field network protocols, 20 672 Field separation, in petroleum processing, 18 645... 

It is by now well established (Kellogg, 1994 Wang and Ehrlich, 1990) that field ion microscopy (FIM) can he used to monitor the diffusion of small clusters of atoms or... 

All major scientific discoveries have prior arts, and STM is no exception. Imaging of individual atoms had been achieved many years before the invention of STM by field-ion microscopy (FIM) and field-emission... 

The art of making sharp tips using electrochemical etching was developed in the 1950s for preparing samples for field ion microscopy (FIM) and field electron spectroscopy (FES). A description of various tip-etching procedures can be found in Section 3.1.2 in the book of Tsong (1990). 

Comparison of Characteristics of Field-Ion Microscopy (FIM) and Laser Resonance Photoion (Electron) Spectromicroscopy (LRFSM)... 

Less generally applicable than electron or scanning probe microscopy - but still capable of revealing great detail - are field emission microscopy (FEM) and field ion microscopy (FIM). These techniques are limited to the investigation of sharp metallic tips, however, with the attractive feature that the facets of such tips exhibit a variety of crystallographically different surface orientations, which can be studied simultaneously, for example in gas adsorption and reaction studies. 

Fig. 7.14 (a) Field ion microscopy (FIM) image of a rhodium tip. As Rh has the fee structure, the fourfold symmetry of the picture implies that the center corresponds to a (100) facet. Dark areas near the four edges of the figure are (111) facets. The arrowhead shows a small defect on the (135) plane, (b) The same Rh tip after adsorption of oxygen followed by field evaporation, leaving oxygen dissolved in the bulk and... 

Field ion microscopy (FIM), atom diffraction (AD) and scanning tunneling microscopy (STM) provide atomic scale information on surface topography. 

Figure 4.26 Motion of isothermal chemical waves at the oscillation mode of the CO oxidation over the top of a platinum needle. The pattern with the atomic resolution is made by field-ion microscopy (FIM), and the photo frames are acquired in the successive several-second intervals [10]. (Courtesy of V. V. Gorodetsky)...

Field ion microscopy FIM High electric field Distribution.of field-... 

A detailed description of the experimental set-up has been given by Block and Czanderna (ref.7). The basic principles are as follows. The catalyst is prepared in the form of a field emitter tip by electrochemically etching a thin wire (0 w 0.1 mm). At its apex this field emitter closely resembles a hemisphere and its surface can be imaged in real space with atomic lateral resolution by field ion microscopy (FIM). 

Low energy electron diffraction is the dominant diffraction method for studying adsorption structures. It gives information in many ways complementary to that obtained from the field ion microscope (i). Brief comparison of LEED with field ion microscopy (FIM) is instructive because these two high resolution methods of finding surface atom positions differ greatly in their actual and potential applications for study of catalysis. 

Two other forms of massive metal deserve a mention. Extremely fine metal tips have been used for Field-Emission Micrpscopy (FEM) and Field-Ion Microscopy (FIM) by the latter technique, atomic resolution of the various planes near the tip can be obtained, and the process of surface migration closely can be studied. 

Field ion microscopy (FIM) also involves a very sharp probe tip, but the tip itself forms the surface over which diffusion occurs [94Kell]. Huge electric fields of a few volts/mn are produced near the tip by surrounding it with a biased imaging screem He or Ne gas is introduced and becomes ionized near protruding atoms on the tip. The ions are accelerated to the surroimding screen and form an image that has atomic-scale resolutiom Oidy refractory metals that form sharp tips may be studied. 

Field ion microscopy (FIM) The specimen is formed into a sharp tip to which a positive potential is applied. The tip is surrounded by inert gas atoms, which are drawn towards it. As they strike, electrons tunnel into the tip leaving the gas atoms ionized. The ions then accelerate away and can be detected as sports on a screen, corresponding to atoms at the tip surface Atomic probe field ion microscopy (APFIM)... 

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