What I want to know is AFM reveals dislocations as hexagonal etch pits, HRXRD also gives an estimation of TDDs by rocking curve broadening etc, TEM also gives an idea about it. Electron channeling contrast imaging also gives an idea by the behavior of back scattered electrons. Which of the above techniques can give an estimate of nearly accurate no of TDDs and give an accurate differentiation of screw, edge and mixed dislocations ? Thank you before hand.
No one knows the technique best among all. But my job is TEM. This is a powerful method, which can provide information on the atomic scale, although in the preparation of the sample is destroyed. You also get only with difficulty infos about larger sample areas. Further, the method is very expensive, compare the attached paper.
In most cases, it is best to aim for a specific combination of available techniques.
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2818.2009.03249.x/pdf
I agree with the above answer that several techniques are usually best. That said TEM is usually the most informative about distinguishing types of defects and accurately counting as long as the sample preparation has not changed the defective. That said it is very time consuming for only a small subset of the area of sample. Getting statistics is difficult.
One other technique that you only mentioned peripherally and is commonly used at least on other materials is highlighting defects with selective etches. After highlighting the defects are visible by AFm as mentioned, but also by SEM and even light microscopy.
As Brent but also Volker already pointed out, TEM is the most safe but also most expensive and time consuming technique (from my point of view). All other techniques are based on the comparison to TEM investigations and show that under very specific conditions one does not always have to use a TEM when the correlation is known. For the inevstigation of a low dislocation density often already light microscopy is sufficient. It also has the charming effect that the statistical relevance is much higher than any other technique. However, the character of the dislocation is certainly not visible (since the differences are too small even for the highest magnifications). Then you have to use one of the higher resolving techniques.
Thank you all for sharing your views. As you guys have already pointed out, TEM is best, however it costly affair and sample preparation is cumbersome, so, does anyone have any idea about rest of the techniques i.e. which among the rest would give a nearly accurate measurement of TDDs?
Cathodoluminescence (CL) imaging is yet another non-destructive method for determining the threading dislocation density
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