Thank You Sir for the answer.

But I am still having doubts regarding what potential range shall I fix based on the CV data. 

I prefer to do a prior LSV and you then chose the potential range that lies in the pssive zone of your electrode.I also suggest to record your scan at 3 kHz. and see if there is any effect.  Good luck.

If you run your CV over a wide potential range, you will see which voltage range result in a mostly flat i vs v behavior. You should run the experiment in that potential range. 

If you don't know what potential range (vs ref) is flat, then start somewhere (probably around where other papers have started). Start with a small potential sweep for maybe 0.2V about that starting point.

Keep running more and more CVs where you expand the potential range by 0.1V in either direction until you see the i vs v diverge from ~linear behavior and become drastically non-linear. At that point, stop extending the potential in that direction but keep extending it in the other direction until you again see some drastic non-linear behavior on the other side of the potential range.

To first approximation, these two potentials will help define the potential window between which you can do your Mott-Schottky analysis.

Keep in mind that the less chemically and structurally uniform your sample, the less clear your CV is likely to be. If principle, if all of your samples are chemically and structurally identical then you can subject 1 sample to this CV harassment to get an idea of the electrochemical behavior of your sample. In practice, samples can differ significantly from one to the next and I encourage you to subject multiple samples to this CV harassment in order to get an idea of general behavior of your electrode under these chemical and potential conditions.

Prof. Artur Braun, could you please share some link or paper for your answer. As far as my understanding goes, we run mott-schottky for the depletion region, while CV is run to check the redox potentials. How can the potential window in CV be used as the depletion region potential window.

Thanks.

@iqra Hambdi, the most important thing when starting your experiment is that you understand it's general response over a range of potentials so that you get an idea of were the depletion regions are and where redox potentials become active, as well as any other funny behavior your sample might have. If you set your CV to a large potential window, you will see where the depletion region is so that you can run your impedance experiment. 

Don't be surprised if the process of running a CV with a large potential window ends up destroying your sample (causing some non-reversible chemical process), this is the price paid for finding out this information. Now that you have a general idea of where to do the impedance experiment, you can do that on another sample.

Hi Kaustav,

You have to really spend some time for obtaining a reliable Mott-Schottky data.

Find a suitable electrolyte (redox couple) for your material. Later, do a CV and find the space charge region. This is mandatory in order to have confidence in your data without degrading the material. The analysis is extremely tricky, but, once you set the proper parameters, it will repeat more than 90%.