Faceting in dilute oxygen atmospheres of group VIA metals

1972 ◽  
Vol 331 (1586) ◽  
pp. 429-443 ◽  
Keyword(s):  
Activation Energy ◽  
Electron Diffraction ◽  
Smooth Surface ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Ordered Structures ◽  
Surface Parameters ◽  
Chemisorbed Oxygen

Certain planes of the group VIA metals, Cr, Mo and W, which are stable in ultra high vacua, readily develop facets when heated at low homologous temperatures in oxygen pressures as low as 10 -6 Pa. We have investigated the (100) and (110) surfaces of these metals by both low energy and reflexion mode high-energy electron diffraction. The (100) surfaces of tungsten and molybdenum readily develop facets which are of {110} and {211} type. The faceting is preceded by the formation of various ordered structures characteristic of chemisorbed oxygen. The (100) surface of chromium is stable in oxygen; however, the (110) surface develops {100} facets. No simple ordered structures are observed on the (110) surface of chromium before faceting and the facets soon disappear beneath epitaxially grown oxide. On all three metals the faceting process is reversible. The smooth surface may be regenerated by heating in the absence of oxygen. The activation energy for this process is high. The effect of faceting on surface parameters is discussed with particular reference to the growth of oxide.

High-energy electron diffraction on Cu(111) measured with low-energy Auger electrons: theory and experiment

1994 ◽  
Vol 306 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
A. Stuck ◽  
M. Nowicki ◽  
S. Mroz ◽  
D. Naumovic ◽  
J. Osterwalder
Keyword(s):  
Electron Diffraction ◽  
High Energy ◽  
Low Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Auger Electrons ◽  
Theory And Experiment

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.

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