I have sprayed silicon solar cells (p-i-n) on a glass substrate. The sprayed films are not stable and can be removed easily by touching it. I think I need to go for annealing of the films but I didn't find any experiment like this in literature.
Should I anneal it before going for I/V measurements or I can proceed with the samples as it is?
As limitations, I can not go beyond 600 C as soda lime glass will not sustain. I tried with Corning glass slides too but it melted at 900 C so please suggest that whether annealing is at all required or not for the experiment.
Would you please describe the structure in a little more detail? What is the cell geometry? Are you sintering metalized contacts? Is the PIN device configured as a substrate structure or superstrate structure?
I have sintered metalized contacts of xtaline cell structures...usually this occurs for a few seconds on a hotplate in air or depending on the contact material the contact may have to be sintered in a reducing gas which includes a safe amount of H2. I have never sintered thin film structures. Usually this will destroy the device at the temperatures you describe.
Ankit,
I unify my vote to Chad and require more than him. In the sintering experiments you carried outو you should evaluated your silicon pin structure. Has it diode characteristic?
I wonder that you would like to raise the sintering temperature in spite of getting a diode characteristics! what type of silicon you have is it a microcrystalline one?
I would assume for thin film solar cells you do not need such high temperature processing of the material!
Wish you success
Dr. Zekry and Dr. Miller,
Thank you for your comments. I would like to apologize for using wrong term "Sintering" over "Annealing". I have updated my question as earlier it may not giving clear understanding. The problem is with the stability of films.
The solar cell is sprayed one on glass substrate coated with ITO then P-i-N structure. I have not yet metalized it or recorded diode characteristics. Silicon is nano-crystalline one.
Dear Ankit,
Now the the things are in order. I would like to say that i do not have direct experience with such process but i would give some working procedure for successful production of the structure.
- Your materials, apparatus and environment must be hyper clean
- Your structure is a multi layer structure, at least for layers to get a working solar cell
- You have to put requirements on very layer such as the thicness, the unifomatity, the granularity. etc.
- You have to define the production process of very layer, method, time post processing
Here you have to at least to bake sprayed film to dry it and even you may anneal it at relatively high temperature to make it harder and remove any rest of solvents.
I thin the success of this step is to get uniform film with he thicness and the conductivity required.
After finishing the first layer successfully you can go to the second layer and proceed in the same manner as the first one
AND so he third till you have the the silicon pin structure on ITO.
You have to limit the temperature to a minimum possible value to avoid interdiffusion of dopants through the i layer.
The final step is the metallization. you need to anneal it at about 450 degree centigrade
It is so that thin film solar cell are fabricated at relatively low temperature.
In all that you must consider the previous work on the same materials. This shorten your experimental efforts.
Wish you success
You can try coating thin layer of Cr or Ni (about 5nm) in order to increase the adhesive of the ITO.
For annealing, 500-600 deg is necessary in nitrogen ambient for 5-20 min.
For higher temperature you may use quartz or sapphire.
Hope this will help you.
Regards.
I did at 580 degree C for 40 minutes but annealed films are not stable and can be removed just by touching.
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