Skip to main content Accessibility help

Exfoliated ∼25μm Si Foil for Solar Cells with Improved Light-Trapping

  • S. Saha (a1), E. U. Onyegam (a1), D. Sarkar (a2), M. M. Hilali (a1), R. A. Rao (a3), L. Mathew (a3), D. Jawarani (a3), D. Xu (a3), R. S. Smith (a3), U. K. Das (a4), J. G. Fossum (a2) and S. K. Banerjee (a1)...


Investigation of optical absorption in ∼25μm thick, monocrystalline silicon (Si) substrates obtained from a novel exfoliation technique is done by fabricating solar cells with single heterojunction architecture (without using intrinsic amorphous silicon layer) with diffused back junction and local back contact. The ease of process flow and the rugged and flexible nature of the substrates due to thick metal backing enables use of various light-trapping and optical absorption enhancement schemes traditionally practiced in the industry for thicker (>120μm) substrates. Optical measurement of solar cells using antireflective coating, texturing on both surfaces, and back surface dielectric/metal stack as mirror to reflect the long wavelength light from the back surface show a very low front surface reflectance of 4.6% in the broadband spectrum (300nm-1200nm). The illuminated current voltage (IV) and external quantum efficiency (EQE) measurement of such solar cell shows a high integrated current density of 34.4mA/cm2, which implies significant internal photon reflection. Our best cell with intrinsic amorphous silicon (i-a-Si) layer with only rear surface textured shows an efficiency of 14.9%. EQE data shows improved blue response and current density due to better front surface passivation. Simulations suggest that with optimized light trapping and surface passivation, such thin c-Si cells can reach efficiencies >20%.



Hide All
1. Honsberg, C., Goodnick, S., and Bowden, S., (International Photovoltaic Reliability Workshop, Tempe, 2009) pp. 28.
2. Green, M.A., Blakers, A., Jiqun, Shi, Keller, E.M. and Wenham, SR, IEEE Trans. Electron Devices ED-31, 679683(1984).
3. Tiedje, T., Yablonovitch, E., Cody, G. D., and Brooks, B. G., IEEE Trans. Electron Devices, ED-31, 711716 (1984).
4. Yablonovitch, E., Cody, G. D., IEEE Trans. Electron Devices ED-29, 300305 (1982).
5. Sakata, H., Tsunomura, Y., Inoue, H., Taira, S., Baba, T., Kanno, H., Kinoshita, T., Taguchi, M., and Maruyama, E., (Proc. 25th EU PVSEC, Valencia, 2010) pp. 1102–1105.
6. Brendel, R., “Thin-film crystalline silicon solar cells: Physics and Technology”, (Weinheim: Wiley-VCH, 2003) pp. 1223.
7. Brendel, Rolf, Solar Energy 77, 969982 (2004).
8. Hebling, C., Glunz, S. W., Schumacher, J. O., and Knobloch, J., (Proc. 14th EU PVSEC, Barcelona, 1997) pp. 2318–2321.
9. Van Nieuwenhuysen, K., Récaman Payo, M., Kuzma-Filipek, I., Van Hoeymissen, J., Van Kerschaever, E., and Poortmans, J., (Proc. 35th IEEE PVSC, Philadelphia, 2009) pp. 000933–000936.
10. Green, M.A., Basore, P. A., Chang, N., Clugston, D., Egan, R., Evans, R., Hogg, D., Jarnason, S., Keevers, M., Lasswell, P., O’Sullivan, J., Schubert, U., Turner, A., Wenham, S. R., and Young, T., Solar Energy 77, 857863 (2004).
11. Mathew, L. and Jawarani, D., U.S. Patent no. 7749884 (July 6, 2010).
12. Dross, F., Milhe, A., Robbelein, J., Gordon, I., Bouchard, P., Beaucarne, G., Poortmans, J., App. Phy. A: Mat. Sc. and Proc. 89, 149152 (2007).
13. Henley, F. J., (Proc. PVSC, Honolulu, 2010) pp. 001184–001192.
14. Rao, R. A., Mathew, L., Saha, S., Smith, S., Sarkar, D., Garcia, R., Stout, R., Gurmu, A., Ahn, D., Xu, D., Jawarani, D., Onyegam, E., Hilali, M., Banerjee, S. K., and Fossum, J., (Proc. EU PVSEC, Hamburg, 2011) pp. 2439–2442.
15. Rao, R. A., Mathew, L., Sarkar, D., Smith, S., Saha, S., Garcia, R., Stout, R., Gurmu, A., Ainom, M., Onyegam, E., Xu, D., Jawarani, D., Fossum, J., Banerjee, S. K., Das, U. K., Upadhyaya, A., Rohatagi, A., and Wang, Q., (Proc. 38th IEEE PVSC, Austin, 2012) pp. 001837–001840.
16. Xu, D., Ho, P. S., Rao, R. A., Mathew, L., Smith, S., Saha, S., Sarkar, D., Vaas, C., and Jawarani, D., (Proc. Reliability Physics Symposium (IRPS), Anaheim, 2012) pp. 4A3.1-4A3.7.
17. Fossum, J. G., Sarkar, D., Mathew, L., Rao, R., Jawarani, D., and Law, M. E., “Back-contact solar cells in thin crystalline silicon, (Proc. 35th IEEE PVSC, Honolulu, 2010) pp. 3131–3136.
18. Law, M. E., and Cea, S. M., Computational Materials Science 12, 289308 (1998).
19. Fossum, J. G., and Shibib, M. A., IEEE Trans. Electron Devices ED-28, 10181025 (1981).
20. Zhao, J., Wang, A., Altermatt, P. P., Wenham, S. R., and Green, M. A., Solar Energy Mater. Solar Cells 4142, 8799 (1996).
21. Cuevas, A., Basore, P. A., Giroult-Maltakowski, G., and Dubois, C., J. Appl. Phys. 80, 33703375 (1996).
22. Taguchi, M., Terakawa, A., Maruyama, E., and Tanaka, M., Prog. Photovoltaics: Res. Appl. 13, 481488 (2005).
23. Cuevas, A, and , D. A, Russell, , Prog. Photovoltaics: Res. Appl. 8, 603616 (2000).
24. Swanson, R. M., (Proc. IEEE Electron Devices Meeting, Dec. 2007) pp. 359–362.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed