yes acceptable.annealing will reduce the grain boundaries near the surface contacts.

Yes, annealing will definitely improve the electrical contact as it reduces the interface trap density at the metal-semiconductor interface. You will have to optimize the annealing recipe in your case i. e. annealing temperature and time. You can find more details in the attached papers.  

Annealing as a post heat treatment is very necessary to join the the junction between the metal and the semiconductor in an atomic scale. It enhances the boding between the the two materials at the interface. In your case it may increase the grains of the semiconductor materials leading to decrease in the grain boundaries. This enhances also the electrical conductivity since the grain boundaries impede the motion on mobile charge carriers. As some colleagues hinted you have to investigate the the optimum conditions for the annealing process. 

Best wishes

Dear Prof. Deepak Kumar Gautam, Prof. Satyendra Kumar Mourya and Prof. Abdelhalim Zekry.

Thank you so much for your reply, ideas, explanation references and suggestion.

Based on your answers it seems now I am in correct direction. 

Now I am more confident to continue this work with that process.

Thank you so much for sharing your knowledge.

All the best and have a good day for all of you. 

Dear Faisal,

I do not know whether I fully agree with what has been said here. The problem with annealing is that you might change the very material you are trying to investigate.

the electrical response of any material equipped with set of two electrodes consists mainly of two parts, the bulk response (the one you seem to be interested in) and the response of the interface. When you start measuring finite current, it does not mean that you are measuring the bulk response. My suggestion would be to make three samples of the same material and with the same electrodes, differeing only in the thickness. Decreasing the thickness by a factor of two, will lead to a decrease of your measured resistance by a factor of two and an increase of your capacitance by a factor of two, if, and only if what you measure is the bulk electrical response. The equipment you need is Electrical Impedance Analyzer. if you have only quasi-dc equipment at your disposal, then you have to rely on measured resistance and if that decreases as suggested, you might consider this resistance to be approximately the bulk resistance.

I hope this comment also helps

With best regards

Petr 

@Prof. Petr Viscor, thank you for your reply.

About post-annealing effect to my sample, since my sample is passivated already and the synthesis temperature is still above the post-annealing temperature I used, I still consider there is no change in the sample, because I checked the xrd and sem after that.

I also carefully think since I have Ti beneath my Pt electrode, so I anneal in Ar environment to prevent oxidation. For Pt, I think it will be no problem since it is noble metal.

How do you think Prof? Is it still acceptable?

Thank you also for your ideas about impedance analysis based on my resistance result. I will try thinking about it.  

Dear Faisal,

it looks that you do think about this possible undesirable effect and that is good. it must be taken into account if some irreversible effects are detected. 

Also, as I have already mentioned, annealing does not remove the interface resistance, it only decreases it (in most cases). But that is often sufficient. The only proper way to make an "Ohmic contacts" is to make your semiconductor degenerate within the thin region at the interfaces (ion implantation), but that is probably impractical in your case.

With best regards

Petr

@Prof. Petr Viscor: Noted Prof., thanks for caring and sharing your knowledge.

Dear All, I am working in the field of the 2D materials. However, I found exactly different behavior in my case. Whenever, I heat the sample like MoS2 fabricated with silver. Device showed the poor IV characteristics in comparison to without heat. What should I do in such case?

And what are the parameter should be focused to overcome this situation.

Dear Abhay,

welcome,

Could you display your I-V characteristics before and after annealing?

If your film is very thin as your case and the metal is fast diffuser like silver then the film can be penetrated by silver leading to microscopic shorts across the film and thereby this results in a large current leakage.

Best wishes

Dear Abhay Vivek Agrawal follow this paper to understand M-S interface resistance Charge carrier injection and transport engineering in two-dimensional transition metal dichalcogenides.

Also Concentrate on

1.Choice of metal electrode because it plays major role inters of band alignment and charge trapping.

2. Annealing temperature and ambient.

3. Quality of your MoS2 (Note : Chemical method MoS2 not suitable for electronic device application especially in Nanoscale)