as I increase the concentration of dopant material there is a peak shift in XRD, Can anyone explain what is the cause of the shifting in my XRD peak?
Need more information. How about shifting due to sample displacement ?
Cud u post the pic of ur refinement ?
thank you Pr. Maykel.
I'm sorry, I didn't understand what is the sample displacement
Please have a look at the following papers which have observed the same behaviour:
Article Synthesis of Ni doped ZnO nanostructures by low temperature ...
Article Photoluminescence Studies on Structural Defects and Room Tem...
Article Influence of structure characteristics on room temperature f...
It is argued that up to ~7-10% Ni content, the ZnO structure can incorporate the NiO into its crystal structure, while for higher concentrations a secondary phase of NiO starts forming, which leads to an expansion of the crystal lattice. This is also why for higher concentrations you start seeing an impurity phase.
Did u do Rietveld refinement? What is NiO wt% at 15% ?
It's hard to see the shifting from that picture, more over u've smoothed ur data.
Dear Banaicha Ismail,
you have a sort of effects.
Ni2+ (0,69A) has an ionic raddi lower than Zn2+(0.75 A). An Isomorphic substitution only, would end up with lower lattice parameters, dislocation to high 2theta values. The oppositive is true.
You may have Ni2+ as interstitial atom in the lattice, in such case, an increase in the cell parameters would shows dislocation to low angles.
It would be expectable to see a reorientation on crystal easy axes occurring, as you increase the Ni amount..
However, not only ionic size is involved, you have a change on crystal growth direction. They have a needle-like shape.
You are seem a medium effect of the overall Ni and Zn amount.
WNM
its only because the ionic radius of Ni is to small compared to the Zn, so shifting toward higher angle is mean that the lattice parameter got reduce, and also this is mean that Ni have been incorporate in your samples
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