Well-Passivated a-Si:H Back Contacts for Double-Heterojunction Silicon Solar Cells: Preprint
We have developed hydrogenated amorphous silicon (a Si:H) back contacts to both p- and n-type silicon wafers, and employed them in double-heterojunction solar cells. These contacts are deposited entirely at low temperature (<250 C) and replace the standard diffused or alloyed back-surface-field contacts used in single-heterojunction (front-emitter only) cells. High-quality back contacts require excellent surface passivation, indicated by a low surface recombination velocity of minority-carriers (S) or a high open-circuit voltage (Voc). The back contact must also provide good conduction for majority carriers to the external circuit, as indicated by a high light I-V fill factor. We use hot-wire chemical vapor deposition (HWCVD) to grow a-Si:H layers for both the front emitters and back contacts. Our improved a-Si:H back contacts contribute to our recent achievement of a confirmed 18.2% efficiency in double-heterojunction silicon solar cells on p type textured silicon wafers.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99GO10337
- OSTI ID:
- 891541
- Report Number(s):
- NREL/CP-520-39911
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
BACK CONTACTS
CHEMICAL VAPOR DEPOSITION
DOUBLE-HETEROJUNCTION
EFFICIENCY
ENERGY CONVERSION
FILL FACTORS
MINORITY CARRIERS
OPEN-CIRCUIT VOLTAGE
ORGANIC COMPOUNDS
PASSIVATION
PV
RECOMBINATION
SILICON
SILICON SOLAR CELLS
SILICON WAFER
SOLAR CELLS
Silicon Materials and Devices
Solar Energy - Photovoltaics
VELOCITY
VOLATILE MATTER