I synthesized Nitrogen doped ZnO . Edax showed the atomic % of N. but how to make sure that dopant in the lattice not on the surface of metal oxide .
You have to undergo edax mapping. here grey scale is converted into RGB pattern, where you can understand at which position your dopant is situated (based on the color difference).
These mapping (very useful in some cases) you must ofcourse study on the cross-section of your material, not on the surface. If nitrogen is distributet uniformly on the cross-section, you probably have what you want.
EDX and EDX mapping on a scanning transmission microscope (STEM) will show the distribution of nitrogen within a particular spot or cross section. The STEM will give a better result than the conventional TEM.
Is it possible for you to etch off the surface of the film and remeasure?
EDAX will have some degree of depth sampling - depends upon your accelerating voltage. So you could be inadvertently getting information from below the surface. Cross-section, as described by others here, would be a good method. Also consider depth profiling by either SIMS or AES. This would provide a measure of uniformity with depth from the surface.
You can sure that doping in lattice of ZnO by the XRD and you can compare between lattice parameters of a,b and c of sample before and after doping. The changing of lattice parameters depending on the radii of that doping decreasing or increasing that value of lattice which cause shifting of the peak position to right or lift side . At same time if the doing on surface , have no change in crystal size and may be get some peak extra belong the oxide of dapant on XRD curve of pure ZnO . For the determine that amount of doing , the best way using EDX and you can analysis the data by using the wt. or ato. % .
Is it a powder or thin film? If it is thin films, there are some techniques available. Most common is elemental depth profiling by SIMS (or even RBS) which will tell you how nitrogen is distributed within your sample (depth). One can also use imaging with SIMS to find the lateral elemental distribution, provided the size of the features 'or' segregation is bigger than a micron. Hope it helps.
Depends on what technique you have easier access and of your material time. If it is a thin film, as mentioned before, EDX mapping of the cross section, XRD measurements, SIMS depth profiling of TOF-SIMS depth profiling will clearly tell you how the N is distributed in your cross-section and not just top. You can also check on XPS - see what is on the top (first 10 nm) and then also do a depth profile - and carefully check the N peak (the one indicating interstitial N).
You can use EPR for this since this nitrogen is a paramagnetic species it will have different properties depending of where it is in the structure. Hope it can help you!
You can use neutron diffraction and make a refinement, then you may know the accurate position of the N atom. On the other hand, the EDX itself can only know the concentration of N atoms, which can not be used to analysis the position of N atom.
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