XRD could also be used to search for peaks characteristic to Ag nanoparticles. This would also confirm doping of the ZnO crystal.

Energy-dispersive X-ray (EDX) spectroscopy can also be used to determine the presences and ratio of elemental compounds such as Zn, O and Ag ions. The presence of Ag ion peaks in the EDS spectrum would confirm doping of the ZnO crystal.

High resolution transmission electron microscopy (HRTEM) images could also be used to visualize the ZnO crystals. By measuring the distances of the planes, the crystal orientation can be determined which is compared to ZnO and Ag planes in the JCPDS database. The presence of planes corresponding to Ag would confirm doping of the ZnO crystals.

What is the estimated dopant concentration? If it is above ~1%(at) then there are several methods that can be used, some described in a previous comment.

Small shifts in the diffraction peak indicate changes in the lattice parameter, which can be caused by the dopants. Quantification would require standards with known compositions, maybe someone already published that so it'll save you work.

Other than XRD, if it's below 1% it can be quite challenging to quantify and even detect.

Electrical measurements, and particularly Hall measurements are very useful as they can provide you with the actual carrier density (and type). However, this may not necessarily be the actual number of dopants, just the electronically active ones. Temperature dependent Hall measurement can further address important aspects in this regard.

A shift in peak position in XRD indicates deformations of the lattice. If Ag is indeed incorporated into ZnO lattice, this is what you would expect to see. The magnitude of the shift should depend on dopant concentration. If you are not sure, you can do a series of experiments, varying dopant concentration. If the shift is consistent with increased concentration, then this is a good indication that doping is successful.

Another method would be EDX in SEM which would give you elemental analysis, as mentioned above. Also, regular elemental analysis, or chemical analysis of your ZnO targeting silver.

Hi!

I am agree with  Dr. Lior Kornblum question.  Quantitative analysis applying XRD is possible only when  the dopant conc. is in %  . If it is less (ppm, ppb), we can use Proton induced X-ray emission (PIXE), X-ray fluorescence ( EDXRF, TXRF etc), Neutron activation analysis (NAA) etc. for its quantification.

Enjoy!

EXAFS 'including µ-EXAFS) and XANES spectroscopies, needind effectively to achieved experiments at a synchrotron x-ray factory are probably of the best techniques providing clear cut (univoke) answers. With XANES (http://en.wikipedia.org/wiki/XANES) and EXAFS (http://en.wikipedia.org/wiki/Extended_X-ray_absorption_fine_structure) - both experiments that might be realized by using the sametype  spectrometer. - also because Zn and Ag elements are relatively closeelect.  d-filling elements

You can access first to the chemical state of both the Zn and Ag elements (e.g. chemical bondings involving at least two of  the three elements), and with EXAFS you will determine separately the atom coordination of each of the metal elements (e.g. for the Ag coordination (neighbour numbers and distances) in O and in Zn, and so and with Zn). Anyway to get univoke answer, you have also to probe parallel your pure ZnO and you pure Ag (in dispersed form if possible), which spectra have to be favourably compared with those of  the composite ZnO(Ag).

µ-EXAFS - for low cencentration doping rate - is made accessible in most of the most recent synchrotron radiation facilities.

Good Luck and Happy New Year

I agree with the comments given by Dr.  Lior Kornblum, that related  to electrical properties

Thanks for your response and your clear illustrations 

I agree with the comment given by L. Kornblum, if, only if the electrical measurements are made on a bulk material and better on single crystal. But is one disposes of powder sample as for XRD, even on sintered powder forming a dense compact it will be rather difficult to extract a clear cut information according to the presence of grain boundaries which can concentrate as well a significant part of the Ag nanoparticles.

Ag is found to increase the conductivity of semiconducting chalcogenide glasses by several orders of magnitude. Conductivity of Ag doped ZnO crystals may also be quite different as compared to undoped one. This can be tried to check the Ag doping in ZnO crystals.

Dear Saad Megahed,

If Ag concentration in ZnO crystals will be not too much one can expect that doped ZnO crystals will have point defects of substitution Zn by Ag. In this case all methods of point defect studies (electrical as it proposed by L.Kornblum, optical absorption specrta, luminescence, photoconductivity as well other methods of transition spectroscopy) are applicable and could be useful to reveal and to identify impurity of Ag.

But if Ag concentration will be enough to form small particles that it will be very difficult to detect these particles by methods for point defect studies. In this case I would recommend to draw attention  on absorption specrta, backward scattering of reflected light and forward scattering of thin plates at different wavelength.  In case of Rayleigh scattering you will have a possibility to estimate particles sizes (averaged).

I wish you good luck in studies.

Thanks for your effort  Dear / Dr A.I. Gribenyukov 

Raman scattering can reveal the dopant.

Hi!

You can prefer Proton Induced X-ray Emission(PIXE), Energy Dispersive X-ray Fluorescence  (EDXRF), T-XRF, Rutherford Beck scattering (RBS)  and few other techniques to estimate the  dopant concentration.

Maybe Spectroscopic ellipsometry can be used as well.

You can try Raman scattering.

The most simplest way is the electrical propertie such as Hall effect experiment

 Details can be aeen from all articles about the scatering effects on electrical conductivity. Themal properties also give such properties, such as seebeck effect, thermal conductivity. In some cases optical properties can is used when activation energies is measured