Kinetics of the degradation and regeneration of p-type multicrystalline silicon under dark anneal
conference paper
In the last few years, it has been found that solar cells made using p-type multicrystalline silicon (mc-Si) wafers
degrade under illumination at elevated temperatures. This degradation is commonly known as light- and elevated
temperature-induced degradation (LeTID) or carrier-induced degradation (CID). CID is the main challenge for
the introduction of mc-Si passivated emitter and rear cells (PERC) in mass production. Previous models of the
CID kinetics are based on the presence of two defects (fast and slow), neglecting the simultaneous regeneration
that may occur during the degradation. Recently, it has been reported that similar degradation can be observed
under anneal at moderate temperatures, even without illumination. In this work, we developed and successfully
validated a new model based on the presence of only one defect and on the simultaneous degradation and
regeneration processes. The model is much simpler than the current available in the literature. We use this model
to investigate the impact of thermal treatment in the dark on p-type mc-Si wafers. We find that high temperatures
lead to faster degradation and regeneration rates, while the degradation extent is larger at low temperatures. The
activation energies of the degradation and regeneration processes are obtained from the proposed model and
found to be 1.08 ± 0.05 eV and 1.11 ± 0.04 eV, respectively. Interestingly, at the end of the dark anneal process,
the samples treated at high temperatures show improvement of ~40% in their effective lifetimes.
degrade under illumination at elevated temperatures. This degradation is commonly known as light- and elevated
temperature-induced degradation (LeTID) or carrier-induced degradation (CID). CID is the main challenge for
the introduction of mc-Si passivated emitter and rear cells (PERC) in mass production. Previous models of the
CID kinetics are based on the presence of two defects (fast and slow), neglecting the simultaneous regeneration
that may occur during the degradation. Recently, it has been reported that similar degradation can be observed
under anneal at moderate temperatures, even without illumination. In this work, we developed and successfully
validated a new model based on the presence of only one defect and on the simultaneous degradation and
regeneration processes. The model is much simpler than the current available in the literature. We use this model
to investigate the impact of thermal treatment in the dark on p-type mc-Si wafers. We find that high temperatures
lead to faster degradation and regeneration rates, while the degradation extent is larger at low temperatures. The
activation energies of the degradation and regeneration processes are obtained from the proposed model and
found to be 1.08 ± 0.05 eV and 1.11 ± 0.04 eV, respectively. Interestingly, at the end of the dark anneal process,
the samples treated at high temperatures show improvement of ~40% in their effective lifetimes.
TNO Identifier
875641
Source title
35th European Photovoltaic Solar Energy Conference and Exhibition
Pages
1-4
Files
To receive the publication files, please send an e-mail request to TNO Repository.