Complete regeneration of BO-related defects in n-type upgraded metallurgical-grade Czochralski-grown silicon heterojunction solar cells

Chang Sun; Daniel Chen; William Weigand; Rabin Basnet; Sieu Pheng Phang; Brett Hallam; Zachary Holman; Daniel Macdonald

doi:10.1063/1.5042460

Complete regeneration of BO-related defects in n-type upgraded metallurgical-grade Czochralski-grown silicon heterojunction solar cells

Chang Sun, Daniel Chen, William Weigand, Rabin Basnet, Sieu Pheng Phang, Brett Hallam, Zachary Holman, Daniel Macdonald

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Complete regeneration of boron-oxygen-related (BO) defects has been demonstrated on n-type upgraded metallurgical-grade (UMG) Czochralski-grown silicon heterojunction solar cells. Under accelerated regeneration conditions (93 suns, 220 °C), V_OC fully recovered in 30-100 s and remained stable during a subsequent stability test. Under milder regeneration conditions (3 suns, 180 °C), the kinetics were slowed down by more than an order of magnitude, but the recovery of V_OC was still complete and stable. The stabilized V_OC of the UMG cells is 709 mV-722 mV, similar to the electronic-grade control cells. We conclude that a significant amount of hydrogen, sourced from the a-Si:H films and possibly the hydrogen plasma treatment, has been introduced into the bulk during the solar cell fabrication processes or the regeneration step. This results in abundant hydrogen concentrations in the bulk of the cells for the purpose of regeneration of BO defects, whether the cell was pre-fired with silicon nitride films (600 °C for 5 s) or not.

Original language	English (US)
Article number	152105
Journal	Applied Physics Letters
Volume	113
Issue number	15
DOIs	https://doi.org/10.1063/1.5042460
State	Published - Oct 8 2018

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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title = "Complete regeneration of BO-related defects in n-type upgraded metallurgical-grade Czochralski-grown silicon heterojunction solar cells",

abstract = "Complete regeneration of boron-oxygen-related (BO) defects has been demonstrated on n-type upgraded metallurgical-grade (UMG) Czochralski-grown silicon heterojunction solar cells. Under accelerated regeneration conditions (93 suns, 220 °C), VOC fully recovered in 30-100 s and remained stable during a subsequent stability test. Under milder regeneration conditions (3 suns, 180 °C), the kinetics were slowed down by more than an order of magnitude, but the recovery of VOC was still complete and stable. The stabilized VOC of the UMG cells is 709 mV-722 mV, similar to the electronic-grade control cells. We conclude that a significant amount of hydrogen, sourced from the a-Si:H films and possibly the hydrogen plasma treatment, has been introduced into the bulk during the solar cell fabrication processes or the regeneration step. This results in abundant hydrogen concentrations in the bulk of the cells for the purpose of regeneration of BO defects, whether the cell was pre-fired with silicon nitride films (600 °C for 5 s) or not.",

author = "Chang Sun and Daniel Chen and William Weigand and Rabin Basnet and Phang, {Sieu Pheng} and Brett Hallam and Zachary Holman and Daniel Macdonald",

note = "Funding Information: This work was supported by the Australian Renewable Energy Agency (ARENA), Project No. RND009, the Australian Centre for Advanced Photovoltaics (ACAP), an ACAP collaboration grant, and the U.S. National Science Foundation and Department of Energy under NSF Cooperative Agreement No. EEC-1041895. Brett Hallam was also supported by the Australian Research Council (ARC) through a Discovery Early Career Researcher Award (No. DE170100620). Apollon Solar is gratefully thanked for the supply of UMG silicon wafers. Publisher Copyright: {\textcopyright} 2018 Author(s).",

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AU - Basnet, Rabin

AU - Phang, Sieu Pheng

AU - Hallam, Brett

AU - Holman, Zachary

AU - Macdonald, Daniel

N1 - Funding Information: This work was supported by the Australian Renewable Energy Agency (ARENA), Project No. RND009, the Australian Centre for Advanced Photovoltaics (ACAP), an ACAP collaboration grant, and the U.S. National Science Foundation and Department of Energy under NSF Cooperative Agreement No. EEC-1041895. Brett Hallam was also supported by the Australian Research Council (ARC) through a Discovery Early Career Researcher Award (No. DE170100620). Apollon Solar is gratefully thanked for the supply of UMG silicon wafers. Publisher Copyright: © 2018 Author(s).

PY - 2018/10/8

Y1 - 2018/10/8

N2 - Complete regeneration of boron-oxygen-related (BO) defects has been demonstrated on n-type upgraded metallurgical-grade (UMG) Czochralski-grown silicon heterojunction solar cells. Under accelerated regeneration conditions (93 suns, 220 °C), VOC fully recovered in 30-100 s and remained stable during a subsequent stability test. Under milder regeneration conditions (3 suns, 180 °C), the kinetics were slowed down by more than an order of magnitude, but the recovery of VOC was still complete and stable. The stabilized VOC of the UMG cells is 709 mV-722 mV, similar to the electronic-grade control cells. We conclude that a significant amount of hydrogen, sourced from the a-Si:H films and possibly the hydrogen plasma treatment, has been introduced into the bulk during the solar cell fabrication processes or the regeneration step. This results in abundant hydrogen concentrations in the bulk of the cells for the purpose of regeneration of BO defects, whether the cell was pre-fired with silicon nitride films (600 °C for 5 s) or not.

AB - Complete regeneration of boron-oxygen-related (BO) defects has been demonstrated on n-type upgraded metallurgical-grade (UMG) Czochralski-grown silicon heterojunction solar cells. Under accelerated regeneration conditions (93 suns, 220 °C), VOC fully recovered in 30-100 s and remained stable during a subsequent stability test. Under milder regeneration conditions (3 suns, 180 °C), the kinetics were slowed down by more than an order of magnitude, but the recovery of VOC was still complete and stable. The stabilized VOC of the UMG cells is 709 mV-722 mV, similar to the electronic-grade control cells. We conclude that a significant amount of hydrogen, sourced from the a-Si:H films and possibly the hydrogen plasma treatment, has been introduced into the bulk during the solar cell fabrication processes or the regeneration step. This results in abundant hydrogen concentrations in the bulk of the cells for the purpose of regeneration of BO defects, whether the cell was pre-fired with silicon nitride films (600 °C for 5 s) or not.

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Complete regeneration of BO-related defects in n-type upgraded metallurgical-grade Czochralski-grown silicon heterojunction solar cells

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