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Tabula Rasa for n -Cz silicon-based photovoltaics

Journal Article · · Progress in Photovoltaics
DOI:https://doi.org/10.1002/pip.3068· OSTI ID:1471291
 [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)
+ Show Author Affiliations

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 degrees 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), Solar Energy Technologies Office (EE-4S)
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, Journal Name: Progress in Photovoltaics Journal Issue: 2 Vol. 27; ISSN 1062-7995
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
English

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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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Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
PV
Tabula Rasa
solar