RHEED

RHEED stands for Reflection High Energy Electron diffraction. RHEED is quite similar to LEED.

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RHEED uses an electron gun and a fluorescent screen for creating pictures showing the structure and/or morphology of a crystal surface.

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RHEED uses much higher electron energy (5-100keV) and lower impact angles (

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In RHEED, the reciprocal lattice is 2-dimensional if the crystal is single crystalline and the surface is flat in nanometer scale. This characteristic makes the reciprocal lattice appear as lines instead of dots in 3-dimensional case. This way the reciprocal lattice lines touch the Ewald-sphere more often than normal and the Laue diffraction condition is fulfilled quite often in the forward direction of the electron beam, where the fluorescent screen is mounted. The diffraction image changes in other cases, depending on the crystallinity and the morphology of the crystal.

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Pros of RHEED:

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Real-Time Analysis: RHEED is often used for monitoring crystal growth, as it doesn't block the direction vertical to the surface of the crystal, which is observed. It's also very sensitive to surface roughness.

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Especially for the crystals that can be easily damaged, MCP-RHEED is used.

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Electron diffraction: Electron diffraction is a technique used to examine solids by firing a beam of electrons at a sample and observing their deflection. The electrons are deflected not as particles but as waves, as in classical diffraction (see Wave-particle duality)....

LEED: LEED acronym stands for Low Energy Electron diffraction, and is a method used for making crystal structures visible.:A LEED system is based on two parts, an Electron gun and a phosphor screen. The electron gun directs an electron beam towards the crystal probe, under normal circumstances impacting v...

Electron gun: An electron gun is a component that produces an electron stream that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology....