Dose the XRD intensity increases with crystallite size?
Is it normal to expect lower FWHM for greater crystallite size?
(I have grown doped and co-doped ZnO samples by RF sputtering which have a strong c-axis orientation with hexagonal wurtzite structure)
Peak width is inversely proportional to crystallite size (check: https://en.wikipedia.org/wiki/Scherrer_equation ). Scherrer equation is suitable for small crystals below 200nm. With a 2D image plate you can cover larger crystal sizes. There is a relation of intensities of individual spots on a spotty diffraction pattern to the crystal size. You need to calibrate intensities with some standard using a ratio between "structure factor/ volume of the elementary unit". Here are two examples form Bob He 2009 and Takashi Ida 2012.
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US7885383.pdf
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US20110064199.pdf
The peak position is essential not affected. The only exception I can think of are stacking faults that may appear in some of the nano materials. In such case Bragg peaks will show some asymmetry
Dear Mallick,
As per theory, sharper XRD peaks provide the structure of large crystallite materials and therefore it was concluded that the peak width for a specific Miller indices of a material is directly related with the mean crystallite size of that materials.
Good luck.
There are standard methods to get the crystal size and strain. You can find them in textbooks or literatures. You may use the W-H method to do linear fitting of your XRD data: line broadening vs scattering angle, to obtain the size and strain.
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