Abstract
Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity beforeARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position andintensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers apathway to increased efficiencies through defect mitigation strategies.
| Original language | American English |
|---|---|
| Number of pages | 6 |
| State | Published - 2012 |
| Event | 2012 IEEE Photovoltaic Specialists Conference - Austin, Texas Duration: 3 Jun 2012 → 8 Jun 2012 |
Conference
| Conference | 2012 IEEE Photovoltaic Specialists Conference |
|---|---|
| City | Austin, Texas |
| Period | 3/06/12 → 8/06/12 |
NREL Publication Number
- NREL/CP-5200-54176
Keywords
- defect luminescence
- photoluminescence
- silicon
- silicon nitride
- silicon processing