Electron microscopy
 
EDS k-Factor Affected by Probe Size
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The k-factors in EDS measurements depend on many factors, e.g. the probe size of the incident electron beam. For instance, Figure 1181 shows the plot of the k-factor corrected Ga/In ratio of the K-lines, taken from a GaIn alloy, as a function of the probe radius (r) and TEM sample thickness (t).

Plot of the k-factor corrected Ga/In ratio of the K-lines as a function of probe radius

Figure 1181. Plot of the k-factor corrected Ga/In ratio of the K-lines as a function of the probe radius (r) and TEM sample thickness (t). [1]

Wood et al. [2] suggested that the x-ray absorption in the sample is not significant (<5%) when the probe size is larger than ~9 nm, while it shows significant absorption if the electron probe is smaller, e.g. in the range of 5-10 nm in diameter.

 

 

 

 

 

 

 

 

 

[1] T. Walther, A comparison of transmission electron microscopy methods to measure wetting layer thicknesses to sub-monolayer precision, Journal of Physics: Conference Series 126, 012091, (2008).
[2] J. E. Wood, D. B. Williams and J. I. Goldstein, Journal of Microscopy, Vol. 133, Pt 3, pp. 255-274, (1984).

 

 

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