I am working on thin film silicon solar cell. I need to know what is the maximum thickness of Si that is considered to be thin film in solar cell technology. Any journal reference regrading this will be extremely helpful in that respect.
Thanks in advance and have a nice day!
I think you mean the thickness of thin film single crystal Si absorbing layer in thin film solar cells. I believe,there is no definition for such limit. The intention is to produce the thinnest possible single crystal solar cell with efficiency approaching that of thick wafer solar cells with thickness of about 250 um. However as a rule of thumb on can consider that tenth of the 250 um would be considered thin film which makes 25um.
On the other side comparable to the thickness of the active layer in thin film solar cells , it must be comparable to the thickness of such thin film solar cells which is in the range of few micrometers.
You can your self obtain many papers when use the key word: thickness of single crystal thin film solar ells.
Best wishes
Dear Uday
I think the thickness of absorber layer relate with absorption coefficient, therefore, when thickness increase the absorption coefficient increase, and verse versa, but this not mean we select the high thickness because this will effect on another properties of device such as diffusion coefficient and reflectivity.
Performance of heterojunction thin film solar cell is basically dependent on the choice of the optimum absorber material because light absorption and the generation of the carriers take place in the absorber layer material. Energy gap of the absorbing material must be small enough to allow absorption of an appreciable portion of solar spectrum and at the same time large enough to minimize the reverse saturation current density. Direct energy gap semiconductors (1.2-1.7 eV) with high absorption coefficient are preferred for the purpose.
Also the diffusion length of the minority carriers must be large enough so that the generated carriers can reach the contacts without much loss. Approximately, thickness of absorber layer greater than 1 um, but you can work about many layers with different thickness, and you can take from its the suitable layer which gives high properties such as energy gap and high absorption coefficient.
With best my wishes
Industrial cells have ~160um. You can do even 50 um. Depends on your light management scheme. Thinner is better for both material and performance if light is well trapped. Thin wafer processing is a challenge.
Dear Uday
Although Si is known a long time ago, it is still unbeatable material in Solar cell bussiness. For absorption, a-Si-H layers enhance the absorption particularly in a thin film Si solar cell. I think 10-30 micron thickness layer could be enough if the cell is designed well and surface light trapping is well engineered. Therefore we could have thin solar cell with the same high efficiency that given by the bulk Si-solar cell.
Best wishes in your work
Following my answer, the absorbtion in a-Si:H could be enhanced by having plasmonic nanoparticles with different distributions (and diameters) to excite resonance modes in visible and IR regimes.
You may see the following paper:
"Increasing the optical absorption in a-Si thin films by embedding gold nanoparticles" https://doi.org/10.1016/j.optmat.2017.10.025
Best wishes
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