yes i have gone through this book .............. i understand two things from this book about Scherrer formula that it has got limitations related to particle size. the other thing i am not sure about is that this formula applies to single phase material. is it correct?

Dear Mr Akbar,

It's a nice question. the required is the value of B i.e width of half maxi ma, it must have some positive value, which depends on the broadening of the peaks.

Thanking you,.

I would like to ask a question to Aseya. Why do you need to obtain information on "crystallite size"? Probably because you want to relate this quantity to some macroscopic property. Scherrer formula gives you informaton on the "diffraction domains". This means for instance that a single grain with coherent grain boundarìes is considered as multi grained, while this boundary will not affect other macroscopic properties like e.g. electrical resistance.

Grain is the domain for many crystallites may be of both similar size or different size crystallites. Character of a grain is completely different from that of crystallite, so it is difficult to derive grain boundaries from the crystallites although both boundaries have contribution towards macroscopic properties if the size is of the order of macroscopic range.

I would like to propose to your attention the article where the coherent scattering domains are determined in CdTe thin films.

Yuriy,

I did not work with CdTe system at all, but it can be possible to get that domain only after going in details of the system.

if you have a broad peaks on XRD you can use the Sherrer''s equation only. If you have a sharp peak you canot use it

Aseya Akbar, please do search RG for "Scherrer" and find the various threads in which (in)applicability of Scherrer's formula is discussed at length. You may also watch out for contributions of Matteo Leoni, who is most competent concerning these questions.