Microcrystalline silicon growth for heterojunction solar cells. Final report, November 1982-January 1984

Technical Report · Wed Feb 01 04:00:00 EST 1984

DOI:https://doi.org/10.2172/7035044· OSTI ID:7035044

Leung, D. C.; Iles, P. A.; Fang, P. H.

Microcrystalline Si (m-Si) films with a 1.7eV energy bandgap and crystal size of several hundred A were e-beam evaporated on single crystalline Si (c-Si) to form a heterojunction with the substrate, or a window layer to a single crystalline p-n junction (heteroface structure). The goal was to enhance Voc by such uses of the larger bandgap m-Si, with the intriguing prospect of forming heterostructures with exact lattice match on each layer. It was found that the heterojunction structure was affected by interface and shunting problems and the best Voc achieved was only 482mV, well below that of single crystal Si homojunctions. The heteroface structure showed promise for some of the samples with p m-Si/p-n structure (the complementary structure did not show any improvement). Although several runs with different deposition conditions were run, the results were inconsistent. Any Voc enhancement obtained was too small to compensate for the current loss due to the extra absorption and poor carrier transport properties of the m-Si film. A study of the m-Si/c-Si interface using a p-p or n-n heterojunction showed that m-Si did not always serve as a minority carrier barrier as expected. The Voc in many samples was of opposite polarity from that predicted which indicated some degree of carrier collection. This raised problems concerning the nature of the m-Si/c-Si interface. In order for this approach to succeed, these interface problems need to be solved along with improvement of the m-Si layer quality.

• Research Organization: Applied Solar Energy Corp., City of Industry, CA (USA); Boston Coll., Chestnut Hill, MA (USA)
• DOE Contract Number: NAS-7-100-956369
• OSTI ID: 7035044
• Report Number(s): DOE/JPL/956369-84/03; ON: DE84013757
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ABSORPTION SPECTRA
CRYSTAL STRUCTURE
DEPOSITION
DIRECT ENERGY CONVERTERS
ELECTRIC POTENTIAL
EQUIPMENT
FABRICATION
HETEROJUNCTIONS
INTERFACES
JUNCTIONS
MICROSTRUCTURE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PLATING
SEMICONDUCTOR JUNCTIONS
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTRA
SPECTRAL RESPONSE
SURFACE COATING
VAPOR PLATING