Fabrication and analysis of high efficiency multicrystalline silicon solar cells
- University Center of Excellence for Photovoltaics, Research and Education, Atlanta, Georgia 30332-0250 (United States)
A detailed investigation of quality enhancement techniques, such as plasma enhanced chemical vapor deposition (PECVD) of SiO{sub 2}/SiN coating, forming gas anneal (FGA) and Al gettering was conducted to improve the performance of cells fabricated on several promising multicrystalline silicon (mcs) materials. A large amount of hydrogen and positive charge in the PECVD SiN antireflection (AR) coating play an important role in passivating surface and bulk defects in silicon. Appropriate post-PECVD deposition anneal was found to be important in maximizing the benefit from PECVD AR coating. Low temperature anneal at 350{degree}C/20 min improves the short wavelength response due to surface passivation along with some increase in the long wavelength response due to bulk defect passivation in certain mcs materials. Post-PECVD rapid thermal anneals (RTA) in the range of 350 to 750{degree}C significantly improve the long wavelength response of certain materials such as EFG silicon. However, this comes at the expense of short wavelength response due to increased absorption in the SiN film. Electron beam induced current (EBIC) measurements revealed significant increase in the intragrain response of these cells after post-PECVD anneal. Al gettering of mcs showed a significant improvement in bulk lifetime and cell efficiency. Forming gas anneal, after phosphorus and Al diffusions, resulted in additional improvements in bulk lifetime in certain materials due to hydrogen passivation. Cells fabricated on cast mcs from Osaka Titanium Corporation (OTC) and Crystal Systems gave cell efficiencies in the range of 17 to 18{percent}. Without the appropriate gettering and passivation techniques these materials give cell efficiencies in the range of 14.5 to 15.5{percent}. {copyright} {ital 1996 American Institute of Physics.}
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 450093
- Report Number(s):
- CONF-9605265-; ISSN 0094-243X; TRN: 9703M0016
- Journal Information:
- AIP Conference Proceedings, Vol. 353, Issue 1; Conference: 13. NREL photovoltaics program review meeting, Lakewood, CO (United States), 16-19 May 1996; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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