Performance Study of the Micromorph Silicon Tandem Solar Cell Using Silvaco TCAD Simulator

  • A. F. Bouhdjar
  • M. Adaika
  • Am. MeftahEmail author
  • R. Boumaraf
  • Af. Meftah
  • N. Sengouga
Regular Paper


This paper is concerned with the numerical modelling of a micromorph silicon tandem solar cell (a-Si:H/µc-Si:H), under series (two-terminal: 2T) and independent (four-terminal: 4T) electrical connection. The study is performed using the simulation software Silvaco TCAD. Both the initial (un-degraded or annealed) state, and the light induced degradation one (well-known Staebler–Wronski effect in a-Si:H) are considered for the studied solar cell, operating under the standard global solar spectrum (AM1.5G). The 2T- and 4T-device optimization is carried out under the effects of the intrinsic (i)-layer thickness of the two sub-cells, and the free carrier mobilities through these layers. By increasing the i-layer thickness of the two sub-cells, the 2T-micromorph tandem cell reveals an optimal conversion efficiency \(\eta\) of 10% and 7.77% corresponding, respectively, to the initial and degraded states. The 4T-configuration exhibits a relatively better \(\eta\) of 10.94% at initial state, reduced only to 9.59% at the degraded one. Further improvement of the 2T and 4T-cell output parameters is obtained by increasing the free carrier mobilities, particularly through the top-cell i-layer. By this way, the better \(\eta\) is also ensured by the 4T-device, which displays an initial state-\(\eta\) of 12.31%, reduced only to 11.43% at the degraded state. However, the improved efficiencies reached by the 2T-configuration are 11.87% and 10.41% corresponding, respectively, to the initial and degraded states.


a-Si:H µc-Si:H Tandem solar cell Micromorph Numerical simulation 



  1. 1.
    D. Carlson, C. Wronski, Amorphous silicon solar cell. Appl. Phys. Lett. 28(11), 671–673 (1976)CrossRefGoogle Scholar
  2. 2.
    J. Meier, S. Dubail, R. Fluckiger, D. Fischer, H. Keppner, A. Shah (eds.), Intrinsic microcrystalline silicon (/spl mu/c-Si:H)-a promising new thin film solar cell material, in 1st World Photovoltaic Specialists Energy Conference (Hawaii, 1994)Google Scholar
  3. 3.
    O. Vetterl, F. Finger, R. Carius, P. Hapke, L. Houben, O. Kluth et al., Intrinsic microcrystalline silicon: a new material for photovoltaics. Sol. Energy Mater. Sol. Cells 62(1), 97–108 (2000)CrossRefGoogle Scholar
  4. 4.
    M. Stutzmann, D.K. Biegelsen, Microscopic nature of coordination defects in amorphous silicon. Phys. Rev. B 40(14), 9834 (1989)CrossRefGoogle Scholar
  5. 5.
    D. Staebler, C. Wronski, Reversible conductivity changes in discharge-produced amorphous Si. Appl. Phys. Lett. 31, 292 (1977)CrossRefGoogle Scholar
  6. 6.
    R.A. Street, Hydrogenated Amorphous Silicon (Cambridge University Press, Cambridge, 2005)Google Scholar
  7. 7.
    A.F. Meftah, A.M. Meftah, A. Merazga, A theoretical study of light induced defect creation, annealing and photoconductivity degradation in a-Si:H. J. Phys.: Condens. Matter 16(18), 3107 (2004)Google Scholar
  8. 8.
    A.F. Meftah, A.M. Meftah, A. Merazga, Created defect under illumination in a-Si:H: hydrogenated or isolated dangling bond? Vacuum 75(3), 269–273 (2004)CrossRefGoogle Scholar
  9. 9.
    A.F. Meftah, A.M. Meftah, A. Merazga (eds.), Modelling of Staebler–Wronski Effect in Hydrogenated Amorphous Silicon Under Moderate and Intense Illumination. Defect and Diffusion Forum (Trans Tech Publ, 2004)Google Scholar
  10. 10.
    Q. Zhang, H. Takashima, J.-H. Zhou, M. Kumeda, T. Shimizu, Metastable-defect generation in hydrogenated amorphous silicon. Phys. Rev. B 50(3), 1551 (1994)CrossRefGoogle Scholar
  11. 11.
    A.F. Meftah, A.M. Meftah, A. Belghachi, Computer simulation of the a-Si:H p–i–n solar cell performance sensitivity to the free carrier’s mobilities, the capture cross sections and the density of gap states. J. Phys.: Condens. Matter 18(41), 9435 (2006)Google Scholar
  12. 12.
    A.F. Bouhdjar, L. Ayat, A.M. Meftah, N. Sengouga, A.F. Meftah, Computer modelling and analysis of the photodegradation effect in a-Si:H p–i–n solar cell. J. Semicond. 36(1), 014002 (2015)CrossRefGoogle Scholar
  13. 13.
    J. Bailat, L. Fesquet, J.-B. Orhan, Y. Djeridane, B. Wolf, P. Madliger et al., Recent developments of high-efficiency micromorph tandem solar cells in KAI-M PECVD reactors, in Proceedings of the 25th EU PVSEC/5th WCPEC (2010), pp. 6–10Google Scholar
  14. 14.
    A. McEvoy, L. Castaner, T. Markvart, Solar Cells: Materials, Manufacture and Operation (Newnes, City of Lithgow, 2012)Google Scholar
  15. 15.
    V. Avrutin, N. Izyumskaya, H. Morkoç, Amorphous and micromorph Si solar cells: current status and outlook. Turk. J. Phys. 38(3), 526–542 (2014)CrossRefGoogle Scholar
  16. 16.
    D. Fischer, S. Dubail, J. Selvan, N.P. Vaucher, R. Platz, C. Hof et al. (eds.), The “micromorph” solar cell: extending a-Si:H technology towards thin film crystalline silicon, in Photovoltaic Specialists Conference, 1996, Conference Record of the Twenty Fifth IEEE (IEEE, 1996)Google Scholar
  17. 17.
    Y. Yang, Towards Application of Selectively Transparent and Conducting Photonic Crystal in Silicon-based BIPV and Micromorph Photovoltaics (2013)Google Scholar
  18. 18.
    P.G. O’Brien, Selectively Transparent and Conducting Photonic Crystals and their Potential to Enhance the Performance of Thin-Film Silicon-Based Photovoltaics and Other Optoelectronic Devices: Department of the Faculty of Materials Science and Engineering, University of Toronto (2011)Google Scholar
  19. 19.
    P. Buehlmann, J. Bailat, D. Dominé, A. Billet, F. Meillaud, A. Feltrin et al., In situ silicon oxide based intermediate reflector for thin-film silicon micromorph solar cells. Appl. Phys. Lett. 91(14), 143505 (2007)CrossRefGoogle Scholar
  20. 20.
    J. Meier, E. Vallat-Sauvain, S. Dubail, U. Kroll, J. Dubail, S. Golay et al., Microcrystalline/micromorph silicon thin-film solar cells prepared by VHF-GD technique. Sol. Energy Mater. Sol. Cells 66(1), 73–84 (2001)CrossRefGoogle Scholar
  21. 21.
    T. Matsui, H. Jia, M. Kondo, Thin film solar cells incorporating microcrystalline Si1–xGex as efficient infrared absorber: an application to double junction tandem solar cells. Prog. Photovolt. Res. Appl. 18(1), 48–53 (2010)CrossRefGoogle Scholar
  22. 22.
    A. Shah, H. Schade, M. Vanecek, J. Meier, E. Vallat-Sauvain, N. Wyrsch et al., Thin-film silicon solar cell technology. Prog. Photovolt. Res. Appl. 12(2–3), 113–142 (2004)CrossRefGoogle Scholar
  23. 23.
    H. Yamamoto, Y. Takaba, Y. Komatsu, M.-J. Yang, T. Hayakawa, M. Shimizu et al., High-efficiency μc-Si/c-Si heterojunction solar cells. Sol. Energy Mater. Sol. Cells 74(1), 525–531 (2002)CrossRefGoogle Scholar
  24. 24.
    L. Hudanski, S. Kasouit, L. Francke, J. Damon-Lacoste, J.-F. Besnier, T. Roschek et al. (eds.), Multiterminal structures for improved efficiency a-Si/μc-Si tandem devices, in Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE (IEEE, 2011)Google Scholar
  25. 25.
    M. Kondo, S. Nagasaki, H. Miyahara, T. Matsui, T. Fujibayashi, A. Sat et al. (eds.), Four terminal cell analysis of amorphous/microcrystalline Si tandem cell, in Photovoltaic Energy Conversion, 2003 Proceedings of 3rd World Conference on (IEEE, 2003)Google Scholar
  26. 26.
    J. Hu, D. Zhong, H. Dang, A. Madan (eds.), Progress in four-terminal nano-crystalline Si/amorphous Si solar cells, in Photovoltaic Specialists Conference, 2005 Conference Record of the Thirty-first IEEE (IEEE, 2005)Google Scholar
  27. 27.
    A. Madan, Flexible displays and stable high efficiency four terminal solar cells using thin film silicon technology. Surf. Coat. Technol. 200(5), 1907–1912 (2005)CrossRefGoogle Scholar
  28. 28.
    F. Dadouche, O. Bethoux, M.-E. Gueunier-Farret, E. Johnson, P.R. i Cabarrocas, C. Marchand et al., Geometrical optimization and electrical performance comparison of thin-film tandem structures based on pm-Si: H and μc-Si: H using computer simulation. EPJ Photovolt. 2, 20301 (2011)CrossRefGoogle Scholar
  29. 29.
    S. Reynolds, V. Smirnov (eds.), Modelling of two-and four-terminal thin-film silicon tandem solar cells, in Journal of Physics: Conference Series (IOP Publishing, 2012)Google Scholar
  30. 30.
    Device Simulator Atlas Ver. 5.10.0.R. Atlas User’s Manual, SILVACO Int., Santa Clara, CA, July (2005)Google Scholar
  31. 31.
    K.-Y. Chan, D. Knipp, A. Gordijn, H. Stiebig, Influence of crystalline volume fraction on the performance of high mobility microcrystalline silicon thin-film transistors. J. Non Cryst. Solids 354(19), 2505–2508 (2008)CrossRefGoogle Scholar
  32. 32.
    B.E. Pieters, Characterization of thin-film silicon materials and solar cells through numerical modeling: Ph.D. Thesis (Delft University of Technology, 2008)Google Scholar
  33. 33.
    K. Shaoying, W. Chong, P. Tao, Y. Jie, Y. Yu, Numerical simulation of the performance of the a-Si:H/a-SiGe: H/a-SiGe: H tandem solar cell. J. Semicond. 35(3), 034013 (2014)CrossRefGoogle Scholar
  34. 34.
    D. Abou-Ras, T. Kirchartz, U. Rau, Advanced Characterization Techniques for Thin Film Solar Cells (Wiley, Hoboken, 2011)CrossRefGoogle Scholar
  35. 35.
    A. Marti, G.L. Araújo, Limiting efficiencies for photovoltaic energy conversion in multigap systems. Sol. Energy Mater. Sol. Cells 43(2), 203–222 (1996)CrossRefGoogle Scholar
  36. 36.
    M. Powell, S. Deane, Improved defect-pool model for charged defects in amorphous silicon. Phys. Rev. B 48(15), 10815 (1993)CrossRefGoogle Scholar
  37. 37.
    M. Powell, S. Deane, Defect-pool model and the hydrogen density of states in hydrogenated amorphous silicon. Phys. Rev. B 53(15), 10121 (1996)CrossRefGoogle Scholar
  38. 38.
    M. Zeman, J. Krc, Optical and electrical modeling of thin-film silicon solar cells. J. Mater. Res. 23(04), 889–898 (2008)CrossRefGoogle Scholar
  39. 39.
    M. Foldyna, K. Postava, J. Bouchala, J. Pistora, T. Yamaguchi (eds.), Model dielectric functional of amorphous materials including Urbach tail, in Microwave and Optical Technology 2003 (International Society for Optics and Photonics, 2004)Google Scholar
  40. 40.
    J. Krc, M. Zeman, F. Smole, Optical modeling of a-Si:H solar cells deposited on textured glass/SnO2 substrates. J. Appl. Phys. 92, 749–755 (2002)CrossRefGoogle Scholar

Copyright information

© The Korean Institute of Electrical and Electronic Material Engineers 2019

Authors and Affiliations

  1. 1.Laboratory of Metallic and Semi-conducting MaterialsUniversity of BiskraBiskraAlgeria

Personalised recommendations