I recently submitted my samples in two different labs, I am getting three very intense peak in between 69-70 (2theta degrees); I want to know what could be the possible reason behind, is it normal to get such peaks with crystalline substrate, or this phenomenon is documented somewhere? Any relevant answers are welcomed. Thank you advance.
It is rare, yet not impossible. For highly unidirectional growth, the associated Bragg peaks could be more intense than the instrument's detection limit and the top of particular peaks might get cut. To obtain a feasible data (i.e., where you can have the full peaks, with intact tops), you may decrease the X-ray emitter current to less than 30 mA. 40 kV - 35 mA is standard for most instruments.
Also watch the maximum value of your y-axis data (intensity in cps). In most instruments detectors can very easily read up-to 104 cps. If your detector fails below this limit, it might be a problem of the instrument. If your data is really beyond that, it definitely is your sample-property.
Hi, with respect, the intensity of the X-ray diffraction line depends on the elemental composition of the sample and its preparation conditions. During the preparation process, the crystallites may take a certain direction for their growth. Samples may have a preferred direction (preferred orientation) for their growth. https://www.researchgate.net/post/why_we_get_different_intensity_peaks_in_XRD
I guess you are using silicon substrate. The peak that you mention is (400) an depending on the mode a) the typical Bragg-Brentano geometry, i.e. in theta-2theta mode, and b) at gracing incident: i.e. 0.5°-2theta. This peak is really intense (with the first mode a). However, this is due to multiple reflection which sometimes appears, but these two modes are only used for powders and not for single crystals. Therefore, the way that you are recording your measurmets is not normal and this peak will appears sometimes
Generally in powder XRD using Cu as X-ray source it is highly unlikely that the most intense peak can come above 2theta value of 60 degrees however it cann't be ruled out. Please make sure that it is not comng from sample holder in case you are using the Tungsten as sample holder.
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction
- XRD Analysis