Surfaces reflection high-energy electron diffraction

The diffraction of electrons can he used to determine the lattice structure. The diffraction can be of a bulk (3D) material or can be from a surface. Reflection high energy electron diffraction (RHEED) is used in epitaxial film growth to monitor film structure during deposition. Electron diffraction can be used in conjunction with transmission electron... 

RHEED Reflection high-energy electron diffraction [78, 106] Similar to HEED Surface structure, composition... 

Ichimiya A, Ohno Y and Horio Y 1997 Structural analysis of crystal surfaces by reflection high energy electron diffraction Surf. Rev. Left 4 501-11... 

This chapter contains articles on six techniques that provide structural information on surfaces, interfeces, and thin films. They use X rays (X-ray diffraction, XRD, and Extended X-ray Absorption Fine-Structure, EXAFS), electrons (Low-Energy Electron Diffraction, LEED, and Reflection High-Energy Electron Diffraction, RHEED), or X rays in and electrons out (Surfece Extended X-ray Absorption Fine Structure, SEXAFS, and X-ray Photoelectron Diffraction, XPD). In their usual form, XRD and EXAFS are bulk methods, since X rays probe many microns deep, whereas the other techniques are surfece sensitive. There are, however, ways to make XRD and EXAFS much more surfece sensitive. For EXAFS this converts the technique into SEXAFS, which can have submonolayer sensitivity. 

Alternatives to XRD include transmission electron microscopy (TEM) and diffraction, Low-Energy and Reflection High-Energy Electron Diffraction (LEED and RHEED), extended X-ray Absorption Fine Structure (EXAFS), and neutron diffraction. LEED and RHEED are limited to surfaces and do not probe the bulk of thin films. The elemental sensitivity in neutron diffraction is quite different from XRD, but neutron sources are much weaker than X-ray sources. Neutrons are, however, sensitive to magnetic moments. If adequately large specimens are available, neutron diffraction is a good alternative for low-Z materials and for materials where the magnetic structure is of interest. 

In the process of MBE, the surface structure can be investigated by reflected high energy electron diffraction (RHEED). During MBE growth, one often observes an oscillation in the intensity of the specular reflected beam as a function of time. This is interpreted to be due to the layer-by-layer growth of a two-dimensional island. 

Surface morphology Reflection high-energy electron diffraction (RHEED) Atomic force microscopy (AFM)... 

Rutherford Backscattering Spectroscopy Reflection High-Energy Electron Diffraction Scanning Electron Microscopy Surface (Sensitive) Extended X-Ray Absorption Fine Structure... 

In-situ growth monitoring, in particular by reflective high energy electron diffraction (RHEED), has provided some fundamental information on the surface and nucleation properties of nitrides. Early RHEED studies by Hughes et al [34] and Hacke et al [49] were completed by Smith et al [50], The observed surface reconstructions for (0001) and (0001) GaN surfaces have allowed the modelling of the quasi-equilibrium surface, which has been calculated to be preferentially Ga-terminated [51], Feuillet et al [52] have followed the evolution of surface lattice constants in RHEED for the nucleation of GaN on AIN or InN on GaN (and vice versa) and extracted a wide range of information on the character of nucleation and misfit relaxation. 

A. Ichimiya and P. I. Cohen, Reflection High-Energy Electron Diffraction , Cambridge University Press, Cambridge, 2004. A comprehensive discussion of practice and theory of RHEED for surface studies. 

An electron reflected from a surface carries diffraction information if it has experienced elastic scattering or information on the excitation of phonons, plasmons, and electronic or vibrational transitions as the result of inelastic events. The major effort in diffraction studies has concentrated on the use of low energies ( 200 eV) but reflection high-energy electron diffraction (RHEED 20—40keV) is suitable also for surface work (see ref. 2 for a description of pattern interpretation). RHEED... 

C. IR/Raman is a computational instrument that predicts IR/Raman spectra. C. LEED/RHEED helps interpret low-energy electron diffraction patterns and reflection high-energy electron diffraction from surfaces. 

The surface and the bulk PSC crystal quality was studied by reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD). Surface chemical compositions were determined with Auger electron spectroscopy (AES) and secondary-ion mass spectrometry (SIMS). Atomic force microscopy (AFM), transmission and scanning electron microscopy (TEM and SEM) were used to monitor PSC morphology and structure. 

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