Reflection High Energy Electron Diffraction (RHEED) is a kind of High Energy Electron Diffraction patterns. It will power for 10 ~ 50 kev single electron beam grazing incidence (1 ° ~ 3 °) to the crystal surface, the reflected beam with crystal surface, and appear on the screen.
RHEED reflective high energy electron diffraction energy into 10 ~ 50 kev monoenergetic electron grazing (1 ° ~ 3 °) to the crystal surface, the reflected beam with crystal surface, and appear on the screen. When the incident beam and crystal cluster Angle theta, spacing, and the electron beam wavelength lambda between satisfied Bragg formula, then along the crystal cluster on the direction of incident beam reflection diffraction beam, so as to get all the information about the structure of the surface.
RHEED incident beam and diffraction intensity big, susceptible to interference, the screen does not need to add high pressure. Positive samples have larger space, is advantageous to the Molecular Beam Epitaxy growth (Molecular Beam Epitaxy, MBE) in situ detection.
RHEED USES the high energy electron, therefore can be formed and focused beam of thin, high brightness of the diffraction spectrum has high intensity and sharpness, achieving a precise monitoring, got all the information structure, and high accuracy.
RHEED can two-dimensional analysis, three dimensional analysis can also be, may be changed by changing the grazing incident Angle and the electron beam penetration depth, in order to obtain depth information.
RHEED by rotating the sample can be directly measured along the reciprocal screw strength changes.
RHEED can not only realize the surface structure analysis, can also be used to observe surface morphology and defects.
RHEED except for single crystal, can also be used for polycrystalline, twin, amorphous surface particles and the surface structure analysis of the sample.
Reflective high energy electron diffraction is widely used and molecular beam epitaxy (MBE) technology development. It can be used for in situ observation of epitaxial film growth, provide the basis for improving conditions. Reflection high energy diffraction has high surface sensitivity (10 to 40), but it is not only confined to the surface of single crystal structure analysis, can also be used for polycrystalline, twin, amorphous surface particles and the surface structure analysis of the sample. Can be used to phase identification, determination of crystal orientation and atomic positions. In addition, the electron diffraction can be used to determine the space group of crystal.
Contact: Nana Zhang
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