Crystallite size in thin films

[wunter k]

Hi, just a question for about a doubt I have regarding the xrd analysis, maybe too trivial for experts...I have estimated the crystallite size in a thin films (my films have 100nm thickness), using rietveld refinement programs. I have always thought that in this way I estimated the size of the grains on the plane, on which I have the main average choerence.
In fact I have found results of about 1500Angstroms.
Is this correct? if the this value refers to the z direction, it should be wrong because higher than the film thickness...so how can I find the size of the crystallites along the direction normal to the sample? Thank you, Wunter.

 

[BigJDubs]

It is difficult to answer this question without further information about the particular sample being analyzed. However, in general, X-ray diffraction (XRD) is most sensitive to the crystallite size in the plane of the sample, which means that the results you obtained are likely to refer to the size of the grains in the plane of the sample. In order to estimate the size of the crystallites normal to the sample, you may need to use other techniques such as transmission electron microscopy or scanning electron microscopy. Alternatively, if your sample is thin enough, you may be able to estimate the size of the crystallites in the direction normal to the sample using XRD by taking a series of measurements at different angles to the sample.