We deposited a metal film on a Ag(100) substrate in the sub-monolayer range. We observe extra spots in LEED (Low Energy Electron Diffraction) after the deposition. We guess the film forms domain (islands) on the substrate as per thermodynamic consideration. Now, is it possible to estimate roughly the average domain size measuring the diameter of these extra spots? Our LEED is an ordinary LEED with beam size in micron range.
Well, yes, just get the inverse of the spot size in the proper units. But with a regular LEED, you will run into the limitation of the spatial correlation length, which probably will be at most a few hundred Angstroms. Do you know that number? (you can estimate it from the width of the substrate spots of a well ordered surface). So the spot of anything ordered on a larger scale will have the same width, and be instrument limited.
Yes. An application of the principals of LEED spot broadening developed by Henzler and Legally are given in the attached paper from my group (the first two references are to the seminal work by the aforementioned). Modern LEED instruments with customized e-guns (SPECS I believe offers such a system) can analyze domain sizes out to about 2000 angstroms.
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