Dopant Compensation within the Intrinsic Poly-Si Isolation Region in Poly-Si/SiOx Passivated IBC Si Solar Cells: Paper No. 020008

Matthew Hartenstein, Caleb Stetson, William Nemeth, Steve Harvey, Sumit Agarwal, Pauls Stradins

Research output: Contribution to conferencePaper

Abstract

We report on the effect of dopant compensation within intrinsic poly-Si regions between p- and n-type fingers of poly-Si/SiOx passivated interdigitated back contact (IBC) solar cells using intrinsic poly-Si as the isolation region between the doped poly-Si fingers. First, we show that dopants from the doped fingers contaminate the intrinsic gap, resulting in doping of the entire intrinsic gap and overlap of the dopant tails from each finger. Next, we show that despite this doping across the gap, shunting between the doped fingers does not occur. We show that this is a result of trap-assisted compensation creating a highly resistive intrinsic region, preventing shunt. We simulate shunt resistance across the gap based on local carrier concentration and deep trap density. We show that trap defects within the poly-Si enhance compensation between the dopant tails. We experimentally confirm these predictions by scanning spreading resistance microscopy of the gap showing ~20 um domain with resistivity ~10^7 ..omega.. cm. Additionally, Kelvin probe force microscopy are compared to finite element simulations which result in the same approximate shape for potential profile, indicating diode behavior across the isolation region. These results demonstrate the powerful effect that trap defects have within the poly-Si isolation region and suggest that precision patterning is not as essential as once thought.
Original languageAmerican English
Number of pages5
DOIs
StatePublished - 2022
EventSiliconPV 2021: The 11th International Conference on Crystalline Silicon Photovoltaics - Hamelin, Germany
Duration: 19 Apr 202123 Apr 2021

Conference

ConferenceSiliconPV 2021: The 11th International Conference on Crystalline Silicon Photovoltaics
CityHamelin, Germany
Period19/04/2123/04/21

NREL Publication Number

  • NREL/CP-5900-79899

Keywords

  • dopant compensation
  • IBC
  • III-V
  • interdigitated back contact
  • photovoltaic
  • poly Si/SiOx
  • PV
  • shunt resistance

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