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Optical reflectance of alkali-textured silicon wafers with pyramidal facets: 2D analytical model

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Abstract

This study presents an analytical model of the reflectance of flat and textured silicon substrates. The model was used to study the reflection behavior of textured silicon surfaces under non-normal incidence. By characterizing the incident light and facets of the silicon wafer with vector geometry, dot products and Phong’s reflection model (https://cs.oberlin.edu/~bob/cs357.08/VectorGeometry/VectorGeometry.pdf) were used to determine the reflection angles between incident light rays and pyramidal facets. The possible optical interactions are considered for a wide range of pyramidal geometries and light incidence angles that are relevant to the exposure of textured silicon surfaces to incident sunlight. Furthermore, the model was used to investigate the possibility of secondary reflection, for the full range of incidence angles to the substrate. The textured silicon surfaces were found to reduce the reflection angles more effectively than flat substrates at lower angles of incidence. Secondary reflection was also found to be experienced or guaranteed, for all pyramid heights, when the angle of incidence to the substrate was less than 19.4°. The predictions are validated with experimental measurements of reflectance from (001)-textured silicon surfaces. The implications of the results are then discussed for the development of micropyramids for improved photoconversion in silicon solar cells.

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References

  1. H. Chung, C. Chen, and H. Chu: Analysis of pyramidal surface texturization of silicon solar cells by molecular dynamics simulations. Int. J. Photoenergy 2008, 1–6 (2008).

    Google Scholar 

  2. J.M. Gee, R. Gordon, and H.F. Laing: Optimization of textured-dielectric coatings for crystalline-silicon solar cells. In Proceedings of the 25th IEEE Photovoltaic Specialists Conference, Washington DC, 1996; pp. 733–736.

    Google Scholar 

  3. J.D. Hylton, A.R. Burgers, and W.C. Sinke: Alkaline etching for reflectance reduction in multicrystalline silicon solar cells. J. Electrochem. Soc. 151 (6), 408–427 (2004).

    Article  Google Scholar 

  4. C.R. Tellier and A. Brahim-Bounab: Anisotropic etching of silicon crystals in KOH solution. J. Mater. Sci. 29 (22), 5953–5971 (1994).

    Article  CAS  Google Scholar 

  5. M. Shikida, K. Sato, K. Tokoro, and D. Uchikawa: Differences in anisotropic etching properties of KOH and TMAH solution. Sens. Actuators, A 80, 179–188 (1999).

    Article  Google Scholar 

  6. H. Seidal, L. Csepregi, A. Henberger, and H. Baumgartel: Anisotropic etching of crystalline silicon in alkaline solutions. J. Electrochem. Soc. 137 (11), 116–125 (1990).

    Google Scholar 

  7. P. Kilpinen, E. Haimi, and V.K. Lindroos: The etch rate variations of p+ silicon wafers in aqueous KOH solutions as a function of processing conditions. MRS Proc. 605, 293 (1999). doi:10.1557/PROC-605-293.

    Article  Google Scholar 

  8. H. Seidal, L. Csepregi, A. Henberger, and H. Baumgartel: Anisotropic etching of crystalline silicon in alkaline solution: Orientation dependence and behavior of passivation layers. J. Electrochem. Soc. 137 (11), 612–626 (1996).

    Google Scholar 

  9. K. Sato, M. Shikida, T. Yamashiro, M. Tsunekawa, and S. Ito: Roughening of single-crystal silicon surface etched by KOH water solutions. Sens. Actuators, A 73, 122–130 (1999).

    Article  CAS  Google Scholar 

  10. L.E. Kassel: KOH-etch related defects on processed silicon wafers. MRS Proc. 259, 187 (1992). doi:10.1557/PROC-259-187.

    Article  CAS  Google Scholar 

  11. C. Yang, P. Chen, Y. Chiou, and R. Lee: Effects of mechanical agitation and surfactant additive on silicon anisotropic etching in alkaline KOH solution. Sens. Actuators, A 119, 263–270 (2005).

    Article  CAS  Google Scholar 

  12. I. Zubel and M. Kramkowska: The effect of isopropyl alcohol on etching rate and roughness of (100) Si surface etched in KOH and TMAH solutions. Sens. Actuators, A 93, 138–147 (2001).

    Article  CAS  Google Scholar 

  13. V. Moroz, J. Huang, K. Wijekoon, and D. Tanner: Experimental and theoretical analysis of the optical behavior of textured silicon wafers. In Proceedings of the 37th IEEE Photovoltaic Specialists Conference. (IEEE, Seattle, WA, 2011); pp. 2900–2905.

    Google Scholar 

  14. X. Zhu, L. Wang, and D. Yang: Investigations of random pyramid texture on the surface of single-crystalline silicon for solar cells. In Proceedings of the ISES Solar World Congress, Beijing, China, (Springer-Verlag, Berlin Heidelberg, Germany, 2007); pp. 1126–1130.

    Google Scholar 

  15. P. Campbell and M.A. Green: Light trapping properties of pyramidally textured surfaces. J. Appl. Phys. 62 (1), 243–249 (1987).

    Article  Google Scholar 

  16. S.C. Baker-Finch and K.R. McIntosh: Reflection distributions of textured monocrystalline silicon: Implications for silicon solar cells. Prog. Photovoltaics Res. Appl. 21 (5), 960–971 (2013). DOI: 10.1002/pip.2186.

    Google Scholar 

  17. S.C. Baker-Finch and K.R. McIntosh: Reflection of normally incident light from silicon solar cells with pyramidal texture. Prog. Photovoltaics Res. Appl. 19 (4), 406–416 (2011). DOI: 10.1002/pip.1050.

    Article  CAS  Google Scholar 

  18. W.C. O’Mara, R.B. Herring, and L.P. Hunt: Handbook of Semiconductor Silicon Technology (William Andrew Inc., Norwich, NY, 1990); pp. 349–352.

    Google Scholar 

  19. D.L. King and M.E. Buck: Experimental optimization of an anisotropic etching process for random texturization of silicon solar cells. In Proceedings of the 22nd IEEE Photovoltaic Specialists Conference, 1991; pp. 303–308.

  20. A. Parretta, A. Sarno, P. Tortora, H. Yakubu, P. Maddalena, J. Zhao, and A. Wang: Angle dependent reflectance measurements on photovoltaic materials and solar cells. Opt. Commun. 172 (1–6), 139–151 (1999).

    Article  CAS  Google Scholar 

  21. J.A. Dziuban: Bonding in Microsystem Technology (Springer, Science & Business Media, 2007); p. 16.

  22. S.C. Baker-Finch: Rules and tools for understanding, modelling and designing textured silicon solar cells. Ph.D. Thesis, Australia National University, 2012.

  23. B. Geitz: Vector Geometry for Computer Graphics. e-Publishing, Part III (2007); pp. 15–16. [Online]. Available: https://cs.oberlin.edu/~bob/cs357.08/VectorGeometry/VectorGeometry.pdf (Accessed August 25, 2013).

    Google Scholar 

  24. K. Wijekoon, T. Weidman, S. Paak, and K. MacWilliams: Production ready novel texture etching process for fabrication of single crystalline silicon solar cells. In Proceedings of the 35th IEEE Photovoltaic Specialists Conference, Honolulu, HI, 2010; pp. 3635–3641.

  25. P.M.M. Bressers, J.J. Kelly, J.G.E. Gardeniers, and M. Elwenspoek: Surface morphology of p-type (100) silicon etched in aqueous alkaline solution. J. Electrochem. Soc. 143 (5), 1744–1750 (1996).

    Article  CAS  Google Scholar 

  26. C.J. Wu, P.J. Wei, and J.F. Lin: The reflectivity of an etched silicon surface with pyramids: I. Theoretical model and its predictions. J. Micromech. Microeng. 19, 1–7 (2009).

    Google Scholar 

  27. P.K. Singh, R. Kumar, M. Lal, S.N. Singh, and B.K. Das: Effectiveness of anisotropic etching of silicon in aqueous alkaline solution. Sol. Energy Mater. Sol. Cells 70, 102–113 (2001).

    Article  Google Scholar 

  28. F.L. Pedrotti, L.S. Pedrotti, and L.M. Pedrotti: Introduction to Optics, 3rd ed. (Pearson Prentice Hall, Upper Saddle River, NJ, 2007).

    Google Scholar 

  29. A. Hamel and A. Chibani: Characterization of texture surface for solar cells. J. Appl. Phys. 10 (3), 231–234 (2010).

    CAS  Google Scholar 

  30. Z. Xi, D. Yang, W. Dan, C. Jun, X. Li, and D. Que: Texturization of cast multicrystalline silicon for solar cells. Semicond. Sci. Technol. 19 (3), 485–489 (2004).

    Article  CAS  Google Scholar 

  31. C. Sethi, V.K. Anand, K. Walia, and S.C. Sood: Optimization of surface reflectance for alkaline textured monocrystalline silicon solar cell. IJCSCT 5 (1), 785–788 (2012).

    Google Scholar 

  32. K.R. McIntosh and S.C. Baker-Finch: OPAL 2: Rapid optical simulation of silicon solar cells. In Proceedings of the 38th IEEE Photovoltaic Specialists Conference, Austin, TX, 2012; pp. 265–271. DOI: https://doi.org/10.1109/PVSC.2012.6317616.

  33. S.C. Baker-Finch and K.R. McIntosh: A freeware program for precise optical analysis of the front surface of a solar cell. In Proceedings of the 35th IEEE Photovoltaic Specialists Conference, Honolulu, HI, 2010; pp. 2184–2187. DOI: https://doi.org/10.1109/PVSC.2010.5616132.

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ACKNOWLEDGMENTS

The authors are grateful to thank Prof. Oleg Yordanov, Bruno Dandogbessi, and Uche Opara for useful scientific discussions. Appreciation is also extended to the World Bank STEP-B Program, the World Bank African Centers of Excellence Program, the African Development Bank, the African Capacity Building Foundation (ACBF), and the Nelson Mandela Institute for financial support.

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Correspondence to Winston Oluwole Soboyejo.

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Fashina, A.A., Kana, M.G.Z. & Soboyejo, W.O. Optical reflectance of alkali-textured silicon wafers with pyramidal facets: 2D analytical model. Journal of Materials Research 30, 904–913 (2015). https://doi.org/10.1557/jmr.2015.70

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  • DOI: https://doi.org/10.1557/jmr.2015.70

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