Reflection high-energy electron diffraction: Difference between revisions

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A RHEED system requires an electron source (gun), photoluminescent detector screen and a sample with a clean surface, although modern RHEED systems have additional parts to optimize the technique.<ref name="ichimiya2004">{{cite book|author=Ichimiya A and Cohen P I|title=Reflection High Energy Electron Diffraction|publisher=Cambridge University Press: Cambridge, UK|year=2004|pages=1,13,16,98,130,161|url=http://books.google.com/books?id=AUVbPerNxTcC&printsec=frontcover|isbn=0-521-45373-9}}</ref><ref name="horio1996">{{cite journal|author=Horio Y, Hashimoto Y, and Ichimaya A|title=A new type of RHEED apparatus equipped with an energy filter| journal=Appl. Surf. Sci.|volume=100|pages=292–6|year=1996|doi=10.1016/0169-4332(96)00229-2|bibcode = 1996ApSS..100..292H }}</ref> The electron gun generates a beam of electrons which strike the sample at a very small angle relative to the sample surface. Incident electrons diffract from atoms at the surface of the sample, and a small fraction of the diffracted electrons interfere constructively at specific angles and form regular patterns on the detector. The electrons interfere according to the position of atoms on the sample surface, so the diffraction pattern at the detector is a function of the sample surface. Figure 1 shows the most basic setup of a RHEED system.

[[File:RHEED Setup.gifsvg|thumbnail|400px|'''Figure 1'''. Systematic setup of the electron gun, sample and detector /CCD components of a RHEED system. Electrons follow the path indicated by the arrow and approach the sample at angle θ. The sample surface diffracts electrons, and some of these diffracted electrons reach the detector and form the RHEED pattern. The reflected (specular) beam follows the path from the sample to the detector.]]

==Surface diffraction==