What is the information obtained from SAED pattern and Convergent beam electron diffraction (CBED) of nanomaterials? is both gives same information or differnt?
There are information which are identical but in a different accuracy. CBED is fantastic for lattice parameter determination. This is only roughly possible with SAED. SAED enables a fast orientation determination, but also the ordering of structures is easy to see. CBED can be used to refine the orientations but it should be hard to find the orientation itself. At least the time you need for this task is longer. Since CBED is very sensitive for lattice parameter changes, strain can be determined. This should be impossible with SAED. Summarizing one can say that SAED is a fast and practically always available technique. CBED is certainly more challenging, needs specific software and clearly more time...and quite perfect crystals. You can still see SAED pattern where CBED doens't show any reliable signal anymore.
Dear Nana
following link might help you to answer your question...
https://books.google.co.in/books?id=-rC5IdzQepEC&pg=PA18&lpg=PA18&dq=What+is+the+information+obtained+from+SAED+pattern+and+Convergent+beam+electron+diffraction+(CBED)+of+nanomaterials&source=bl&ots=48MOxI6BvE&sig=_uRLE-D111FnWj-3SPR6s66_23E&hl=en&sa=X&ved=0ahUKEwi6i5zah6LMAhVmIaYKHZHuB8UQ6AEIODAJ#v=onepage&q=What%20is%20the%20information%20obtained%20from%20SAED%20pattern%20and%20Convergent%20beam%20electron%20diffraction%20(CBED)%20of%20nanomaterials&f=false
Dear Nana,
In general, the comparison of SAED and CBED diffraction is the same as the lite and full version of any software. If you require serious crystallographic information you have to turn your TEM to CBED configuration. However, both techniques has own requirements on sample properties. One of them is thickness or particle size. For 10-20 nm particle SAED may be useless because of relatively paralel beam, huge irradiated area, and so on. CBED use a convergent beam which gives a better spatial resolution.
The problem of CBED is the well known term "best sample thickness". At the thickness ~50-60 nm and less you can lost some analytical information. Very thick sample has the similar effect. So suitability of CBED for nanomaterials depends on what you need to read out from diffraction data.
- Badges
- Science method