We have CuS thin film with (Cu:S) molar ratio (1:1), and we got nanoplates and very distinct and clear particles on the surface. But when increase S concentration (1:2) and (1:3) for (0.1 M, 0.2 M and 0.4 M), the film surface became non-specified aggregated particles (actually there is no particles just aggregations) with porosity. Any explanation for this significant change in surface morphology?
Many thanks in advance for your help and your time
Best regards
Fayroz
Just to study the characteristics of the film and to find if it will give better results or not. Actually I found the best films are of molar ratio (1:1). But I need an explanation for the other molar ratios, why the FESEM images for them didn't give any good surface or specific particles? What is the effect of S (orthorhombic crystal structure) on the thin film morphology?
First of all u must check that u are getting a pure phase or not in all these conditions.
May be u are getting some other phase/material that is changing the morphology of ur sample. If not so ... that may be nothing but extra sulfur. Rinse the films properly before FESEM. It may change ur results.
Dear Sandeep Munjal
Thanks for your reply. All the samples have pure CuS covellite phase.
Thank you for your help.
Dear Fayroz A Sabah
Have a nice time and good day.
Firstly you should have a look to the phase diagram and the available ratio or concentration of doping or alloying through the following book before you start to do any thing.
the book title is: Z.U. Boresova (Ed.), Glassy Semiconductors, Plenum Press, New
York and London, 1978
Yours
A. El-Denglawey
Dear A. Eldenglawey
Sweet greetings
Thank you very much for your interest and help, I got the book and will see how can I benefit from it.
Many thanks with regards
Fayroz
What solvent , deposition parameters, especially the substrate and temperature and deposition technique are used in fabrication of CuS thin films ?
I used Deionised water as a solvent, deposition temperature 200 oC, glass substrate, using spray pyrolysis deposition.
All the parameters were the same for all depositions, only change the concentration 0.1 M, 0.2 M and 0.4 M. Then change the molar ratio (1;1), (1:2), and (1:4) for each concentration.
What are actual concentrations of Cu source and sulfur source? What is the sulfur source used, thiourea? With increase in the concentration of sulfur source, at higher concentration, coagulated sulfur is likely to form in the solution and the solution will no longer will be clear, as when prepared. During pyrolysis, based on the substrate temperature, it may lead to formation of particulate on the surface. From XRD, if the concentration of these particulates is less than the detection limit , the corresponding peaks may not be indicated. If you check, through EDAX, these regions, it could give some clue.
All the best
Sundara Raja V
Dear Sundara Raja Vanjari
Thank you very much, you referred to very important point which is the sulfur source. I tried to use thiourea, but really I faced a big problem as the solution become coagulated to high extent, which cannot be spray at all. So instead I used Na2S2O3.5H2O as a source for S and CuCl2.2H2O as a source for Cu. This solution was very suitable for spray. XRD results didn't give various peaks. EDX results gave high rate of S in some regions, but in another regions the ratio of S and Cu is equal.
Really appreciate your interest, many thanks
Regards
Fayroz
Dear Sabah
I feel you do not have any problem even with thiourea, as long as you keep the thiourea concentration quite low. You can achieve Cu:S 1:1 by choosing 0.1 M : 0.1 M or 0.01 M :0.01 M or other lower concentrations. The problem is with the higher molar ratios. I suggest you restrict Cu salt concentration to 0.01 M or even less and accordingly choose thiourea concentration and I am sure you will get good films. The surface rough could be only those of coagulated sulfur or Cu-S complex as you could witness from EDS analysis in some regions.
best wishes
VSR
I think you must to make one experiment to dilute one suspension before spraying,sometimes dilution is an efficient way to avoid aggregation
Dear Sundara Raja Vanjari
Thanks a lot, I got from your answer that thiourea will give good result only at low concentration, I already did all my experiments on Na2S2O3.5H2O sodium thiosulphate. So I didn't have experience with thiourea.
Thanks again for the information
Best regards
Fayroz
Dear Hassan Alshamsi
Thank you for your interest, I have no problem with aggregation as much as I have problem with the structure shape. I want to explain why it change?
Many thanks with regards
Fayroz
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