COMPARISON OF LOW‐ENERGY ELECTRON DIFFRACTION AND LOW‐ANGLE, HIGH‐ENERGY ELECTRON DIFFRACTION TECHNIQUES FOR THE OBSERVATION OF CHEMISORPTION

1965 ◽  
Vol 7 (6) ◽  
pp. 173-175 ◽  
Author(s):  
Don F. Mitchell ◽  
Gary W. Simmons ◽  
Kenneth R. Lawless
Keyword(s):  
Electron Diffraction ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

Microprobe AES Combined With Scanning RHEED Microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 368-369
Author(s):  
Y. Sakai ◽  
S. Kitamura ◽  
A. D. Buonaquisti
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
Diffraction Spot ◽  
High Energy Electron ◽  
Micro Structure ◽  
Fluorescent Screen ◽  
Low Energy Electron

Surface micro-structure analysis is very important for surface study in material science. Observations of surface atomic steps and reconstructed structures have been made using several techniques: reflection high energy electron microscopy (RHEEM), low energy electron reflection microscopy (LEERM) and low energy electron diffraction microscopy (LEEDM).In the present experiment, observations of surface micro-structures have been made using a scanning type reflection high energy electron diffraction (RHEED) microscopy. This technique has certain advantages of easy combinations with multiple surface analyzing techniques such as scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS).A schematic diagram of the scanning RHEED microscope combined with the microprobe AES is shown in Fig. 1. RHEED patterns are observed on the fluorescent screen through a viewing port. To observe the micro-structure (scanning RHEED image or dark field image), a particular diffraction spot is selected by means of the other small fluorescent screen with an aperture.

scholarly journals Surface crystallography with low-energy electron diffraction

1993 ◽  
Vol 442 (1914) ◽  
pp. 61-72
Keyword(s):  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Surface Crystallography

Bragg’s 1913 publication of the principles of X-ray crystallography came only a year after von Laue’s discovery of X-ray diffraction from crystals. Structure determination (of small molecules) with high-energy electron diffraction followed by just three years the 1927 discovery of electron diffraction by Davisson and Germer. By contrast, low-energy electron diffraction (LEED) would require four more decades before yielding its first structure determinations (of surfaces) around 1970. The delay was primarily due to the need for ultra-high vacuum and to a lesser extent to the need for a suitable theory to model multiple scattering. This review will sketch the development of surface crystallography by LEED and describe its principles and present capabilities.

Analysis of Surface Structural Defects by Low Energy Electron Diffraction

1981 ◽  
Vol 10 ◽  
Author(s):  
D. G. Welkie ◽  
M. G. Lagally
Keyword(s):  
Electron Diffraction ◽  
Grazing Angle ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
Analytical Models ◽  
Structural Defects ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Antiphase Domains

The characterization of surface structural defects by low energy electron diffraction is discussed. The identification of crystal mosaic structure, random strain, antiphase domains and steps is emphasized, and it is shown that they produce characteristic effects in the angular distribution of intensity in diffracted beams. Analytical models are summarized. They are also applicable to other surfacesensitive diffraction techniques such as reflection high energy electron diffraction and grazing angle X-ray diffraction. The quantitative analysis of these several types of defects is illustrated by measurements on the surface of an epitaxially grown Ag(111) film and on a sputter-etched and annealed GaAs(110) surface.

Formation of a Ba-Te Surface on GaAs

2003 ◽  
Vol 782 ◽  
Author(s):  
Kevin A. Boulais ◽  
Francisco Santiago ◽  
Karen J. Long ◽  
Victor H. Gehman
Keyword(s):  
Electron Diffraction ◽  
Photoelectron Spectroscopy ◽  
Molecular Beam ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Polycrystalline Form

ABSTRACTThe formation of a Ba-Te surface on GaAs has been investigated. The surface was created using molecular beam epitaxy (MRS). A GaAs (100) surface was first exposed to Te and characterized using x-ray photoelectron spectroscopy (XPS), reflective high energy electron diffraction (RHEED) and low energy electron diffraction (LEED). The Te-reacted surface was then exposed to BaF2 flux producing a second reaction. In this reaction, the BaF2 dissociated leaving barium on the surface but no fluorine. This is in contrast to the clean (no tellurium) GaAs (100) surface in which BaF2 has been shown to grow single crystal. Although high order exists during early stages of the Ba-Te growth, further exposure gives way to a polycrystalline form. This paper discusses the formation and analysis of the Ba-Te surface.

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