Current Applied Physics

Korean Physical Society (한국물리학회)
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Potential of chemical rounding for the performance enhancement of pyramid textured p-type emitters and bifacial n-PERT Si cells

  • Song, Inseol (KU-KIST Green School, Graduate School of Energy and Environment, Korea University) ;
  • Lee, Hyunju (Toyota Technological Institute) ;
  • Lee, Sang-Won (Department of Materials Science and Engineering, Korea University) ;
  • Bae, Soohyun (Department of Materials Science and Engineering, Korea University) ;
  • Hyun, Ji Yeon (Department of Materials Science and Engineering, Korea University) ;
  • Kang, Yoonmook (KU-KIST Green School, Graduate School of Energy and Environment, Korea University) ;
  • Lee, Hae-Seok (KU-KIST Green School, Graduate School of Energy and Environment, Korea University) ;
  • Ohshita, Yoshio (Toyota Technological Institute) ;
  • Ogurad, Atsushi (School of Science and Technology, Meiji University) ;
  • Kim, Donghwan (KU-KIST Green School, Graduate School of Energy and Environment, Korea University)
  • Received : 2018.05.03
  • Accepted : 2018.07.09
  • Published : 2018.11.30
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Abstract

We have investigated the effects of chemical rounding (CR) on the surface passivation and/or antireflection performance of $AlO_{x^-}$ and $AlO_x/SiN_x:H$ stack-passivated pyramid textured $p^+$-emitters with two different boron doping concentrations, and on the performance of bifacial n-PERT Si solar cells with a front pyramid textured $p^+$-emitter. From experimental results, we found that chemical rounding markedly enhances the passivation performance of $AlO_x$ layers on pyramid textured $p^+$-emitters, and the level of performance enhancement strongly depends on boron doping concentration. Meanwhile, chemical rounding increases solar-weighted reflectance ($R_{SW}$) from ~2.5 to ~3.7% for the $AlO_x/SiN_x:H$ stack-passivated pyramid textured $p^+$-emitters after 200-sec chemical rounding. Consequently, compared to non-rounded bifacial n-PERT Si cells, the short circuit current density Jsc of 200-sec-rounded bifacial n-PERT Si cells with ~60 and ${\sim}100{\Omega}/sq$ $p^+$-emitters is reduced by 0.8 and $0.6mA/cm^2$, respectively under front $p^+$-emitter side illumination. However, the loss in the short circuit current density Jsc is fully offset by the increased fill factor FF by 0.8 and 1.5% for the 200-sec-rounded cells with ~60 and ${\im}100{\Omega}/sq$ $p^+$-emitters, respectively. In particular, the cell efficiency of the 200-sec-rounded cells with a ${\sim}100{\Omega}/sq$ $p^+$-emitter is enhanced as a result, compared to that of the non-rounded cells. Based on our results, it could be expected that the cell efficiency of bifacial n-PERT Si cells would be improved without additional complicated and costly processes if chemical rounding and boron doping processes can be properly optimized.

Keywords

Acknowledgement

Supported by : Korea Institute of Energy Technology Evaluation and Planning (KETEP)

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