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

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 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.

Authors:
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)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1471291
Alternate Identifier(s):
OSTI ID: 1464649
Report Number(s):
NREL/JA-5900-71883
Journal ID: ISSN 1062-7995
Grant/Contract Number:  
AC36-08GO28308; DEEE00030301
Resource Type:
Accepted Manuscript
Journal Name:
Progress in Photovoltaics
Additional Journal Information:
Journal Volume: 27; Journal Issue: 2; Journal ID: ISSN 1062-7995
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; PV; solar; Tabula Rasa

Citation Formats

LaSalvia, Vincenzo, Youssef, Amanda, Jensen, Mallory A., Looney, Erin E., Nemeth, William, Page, Matthew, Nam, Wooseok, Buonassisi, Tonio, and Stradins, Paul. Tabula Rasa for n -Cz silicon-based photovoltaics. United States: N. p., 2018. Web. doi:10.1002/pip.3068.
LaSalvia, Vincenzo, Youssef, Amanda, Jensen, Mallory A., Looney, Erin E., Nemeth, William, Page, Matthew, Nam, Wooseok, Buonassisi, Tonio, & Stradins, Paul. Tabula Rasa for n -Cz silicon-based photovoltaics. United States. doi:10.1002/pip.3068.
LaSalvia, Vincenzo, Youssef, Amanda, Jensen, Mallory A., Looney, Erin E., Nemeth, William, Page, Matthew, Nam, Wooseok, Buonassisi, Tonio, and Stradins, Paul. Tue . "Tabula Rasa for n -Cz silicon-based photovoltaics". United States. doi:10.1002/pip.3068. https://www.osti.gov/servlets/purl/1471291.
@article{osti_1471291,
title = {Tabula Rasa for n -Cz silicon-based photovoltaics},
author = {LaSalvia, Vincenzo and Youssef, Amanda and Jensen, Mallory A. and Looney, Erin E. and Nemeth, William and Page, Matthew and Nam, Wooseok and Buonassisi, Tonio and Stradins, Paul},
abstractNote = {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.},
doi = {10.1002/pip.3068},
journal = {Progress in Photovoltaics},
number = 2,
volume = 27,
place = {United States},
year = {2018},
month = {8}
}

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