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Title: Tabula Rasa for n -Cz silicon-based photovoltaics

Journal Article · · Progress in Photovoltaics
DOI:https://doi.org/10.1002/pip.3068· OSTI ID:1471291
ORCiD logo [1];  [2];  [2];  [2];  [1];  [1];  [3];  [2];  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. Woongjin Energy Co. Ltd., Daejoen (Korea, Republic of)
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Abstract High‐temperature annealing, known as Tabula Rasa (TR), proves to be an effective method for dissolving oxygen precipitate nuclei in n‐ Cz silicon and makes this material resistant to temperature‐induced and process‐induced lifetime degradation. Tabula Rasa is especially effective in n ‐Cz wafers with oxygen concentration >15 ppma. Vacancies, self‐interstitials, and their aggregates result from TR as a metastable side effect. Temperature‐dependent lifetime spectroscopy reveals that these metastable defects have shallow energy levels ~0.12 eV. Their concentrations strongly depend on the ambient gases during TR because of an offset of the thermal equilibrium between vacancies and self‐interstitials. However, these metastable defects anneal out at typical cell processing temperatures ≥850°C and have little effect on the bulk lifetime of the processed cell structures. Without dissolving built‐in oxygen precipitate nuclei, high‐temperature solar cell processing severely degrades the minority carrier lifetimes to below 0.1 millisecond, while TR‐treated n ‐Cz wafers after the cell processing steps exhibit carrier lifetimes above 2.2 milliseconds.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1471291
Alternate ID(s):
OSTI ID: 1464649
Report Number(s):
NREL/JA-5900-71883
Journal Information:
Progress in Photovoltaics, Vol. 27, Issue 2; ISSN 1062-7995
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

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Cited By (1)

22.6% Efficient Solar Cells with Polysilicon Passivating Contacts on n‐type Solar‐Grade Wafers journal August 2019

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