Journal of Taibah University for Science (Dec 2019)

High efficiency silicon solar cells with back ZnTe layer hosting IPV effect: a numerical case study

  • M. Boumaour,
  • S. Sali,
  • S. Kermadi,
  • L. Zougar,
  • A. Bahfir,
  • Z. Chaieb

DOI
https://doi.org/10.1080/16583655.2019.1623476
Journal volume & issue
Vol. 13, no. 1
pp. 696 – 703

Abstract

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To get enhanced long-wavelength absorption, an impurity photovoltaic (IPV) mechanism was implemented within a transparent conducting oxide (TCO) at the rear of a solar cell. The numerical simulation of the N+/P (silicon)/IPV-TCO device was carried out by using SCAPS-1D program which allows the inclusion of optically active defects. In the proposed heterostructure configuration, ZnTe is a suitable material as back surface reflector. In analyzing the Si/ZnTe interface, lattice mismatch, energy band alignment and defects density were considered with appropriate treatment. In particular, to cure the detrimental 12% lattice mismatch at the interface, a thin silicon amorphous layer was inserted in-between, allowing 22.98% conversion efficiency. With adapted ZnTe Lucovsky's model for the optical capture cross sections and introduction of an oxygen radiative IPV defect (O2 level at 0.4 eV below the conduction band), a conversion efficiency of 27.15% was ultimately achieved. The experimental feasibility of the high-efficiency heterostructure device is evaluated.

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