For AZO films, the XRD results are showing an decrease in the crystallite size were measured using Scherrer's equation as a parameter of annealing time increases. Can some one suggest me that what may be the possible reason for decrease in the crystallite size of AZO as increase in annealing time? Thanks
Dear colleague Dr. Narendra Bandaru
Have a nice time and good day.
Annealing may affect the crystallite size to be high or low. What is the reason? Firstly, the crystallite size increases or decreases according to the the ordering inside the material (density of localized states); low or high respectively. XRD, SEM and TEM are useful techniques to study the effect of annealing on the structural properties of the focused material. The lower the ordering inside material the lower crystallie size. If the annealing has a positive effect on the focused material the crrystallie size will increase and vice versa.
Ex. if the intensity if XRD increases and the FWHM decreases with the increasing of annealing, this is a document that the increasing of annealing gives more enhancement of order and the crystallie size will increases by the increasing of annealing. TEM can confirm the XRD data and SEM gives you what happen for the surface morphology. SEM can give you also if the sample under consideration has a porous nature or not; porous nature has an important effect on the ordering of material and consequently the crystallite size; both of them are strongly affect by annealing.
Secondly, If the annealing temperature is not appropriate (higher than the crystallization temperature or near the melting point then the bonds of material will be broken and the order through the focused material will be increase and consequently the crystallite size will be decreased.
Thirdly, to decide the appropriate annealing temperature you should make DTA or DSC for your sample.
I wish this is useful and help you.
Yours
A. El-Denglawey
I think that is related with the transformation of phases as well reducing in a spacing of the level crystal as the temperature increase with time.
Regards,
Dear colleague Dr. Narendra Bandaru
Have a nice time and good day.
Annealing may affect the crystallite size to be high or low. What is the reason? Firstly, the crystallite size increases or decreases according to the the ordering inside the material (density of localized states); low or high respectively. XRD, SEM and TEM are useful techniques to study the effect of annealing on the structural properties of the focused material. The lower the ordering inside material the lower crystallie size. If the annealing has a positive effect on the focused material the crrystallie size will increase and vice versa.
Ex. if the intensity if XRD increases and the FWHM decreases with the increasing of annealing, this is a document that the increasing of annealing gives more enhancement of order and the crystallie size will increases by the increasing of annealing. TEM can confirm the XRD data and SEM gives you what happen for the surface morphology. SEM can give you also if the sample under consideration has a porous nature or not; porous nature has an important effect on the ordering of material and consequently the crystallite size; both of them are strongly affect by annealing.
Secondly, If the annealing temperature is not appropriate (higher than the crystallization temperature or near the melting point then the bonds of material will be broken and the order through the focused material will be increase and consequently the crystallite size will be decreased.
Thirdly, to decide the appropriate annealing temperature you should make DTA or DSC for your sample.
I wish this is useful and help you.
Yours
A. El-Denglawey
Dear colleague Dr. Narendra Bandaru
Have a nice time and good day.
I had mentioned in my previous answer to DTA and DSC, herein find attached figure to show you how to deal with DTA or DSC to identify the range of annealing temperature. There are four parameters you can determine from DTA or DSC; glass transition, Tg, the onset of crystallization, Tc, Peak of crystallization, Tp and melting point Tm. Please see the attached file.
I wish this is useful and help you.
Yours
A. EL-Denglawey
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