Reflection high-energy electron diffraction: Difference between revisions

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===Film growth===

RHEED is an extremely popular technique for monitoring the growth of thin films. In particular, RHEED is well suited for use with [[molecular beam epitaxy]] (MBE), a process used to form high quality, ultrapure thin films under ultrahigh vacuum growth conditions.<ref name="atwater1997">{{cite journal|author=Atwater H A|author2=Ahn C C|author3=Wong S S|author4=He G|author5=Yoshino H|author6=Nikzad S|last-author-amp=yes|title=Energy-Filtered Rheed And Reels For In Situ Real Time Analysis During Film Growth|journal=Surf. Rev. And Lett.|volume=4|pages=525|date=1997|doi=10.1142/S0218625X9700050X|bibcode = 1997SRL.....4..525A|issue=3 }}</ref> The intensities of individual spots on the RHEED pattern fluctuate in a periodic manner as a result of the relative surface coverage of the growing thin film. Figure 8 shows an example of the intensity fluctuating at a single RHEED point during MBE growth.

[[File:Oscilatting function.gif|thumbnail|400px|'''Figure 8'''. The curve is a rough model of the fluctuation of the intensity of a single RHEED point during MBE deposition. Each peak represents the forming of a new monolayer. Since the degree of order is at a maximum once a new monolayer has been formed, the spots in the diffraction pattern have maximum intensity since the maximum number of diffraction centers of the new layer contribute to the diffracted beam. The overall intensity of the oscillations is dropping the more layers are grown. This is because the electron beam was focused on the original surface and gets out of focus the more layers are grown. Note that the figure is only a model similar in shape to those used by film growth experts.]]