Vacuum deposited polycrystalline silicon films for solar cell applications. Final report, 29 September 1978-30 September 1979
The DOE goal of obtaining low-cost, 10% efficient solar cells was approached through the development of a potentially all-vacuum fabrication process incorporating vacuum deposited, thin-film, polycrystalline silicon. Experimental devices were constructed in layers as follows: alumina substrate/TiB/sub 2/ bottom electrode/p-type polycrystalline silicon film/diffused silicon n-region/Ti-Ag electrode. An essential feature of this design is the TiB/sub 2/ bottom electrode which is stable with respect to silicon up to 1200/sup 0/C and remains conducting after the silicon deposition. Grain growth, film composition and interfacial analyses, and photovoltaic characteristics were investigated using secondary-ion mass spectrometry (SIMS), X-ray diffraction and conventional electronics measurements techniques. Average grain diameters in the films parallel to the substrate were 5 ..mu..m. Phosphorus was diffused into the silicon film using standard techniques to create n-p junctions. Al, Ti, and Ti/Ag electrodes were used as top contacts to the n-type layer. Typical of the best photovoltaic responses from small grained devices without antireflection coating or electrode geometry optimization were V/sub oc/ = 0.26V, J/sub sc/ = 16 mA/cm/sup 2/, efficiency 2.2% and fill factor 0.54. The highest V/sub oc/ observed to date is 0.38V; the highest efficiency is 2.6%. Carrier concentrations were obtained by both Hall effect and SIMS measurements; diffusion lengths were determined by the short-circuit current vs incident light wavelength method. SIMS was used extensively in the examination of interactions at each interface. Results are presented and discussed.
- Research Organization:
- Johns Hopkins Univ., Laurel, MD (USA). Applied Physics Lab.
- DOE Contract Number:
- ET-78-A-03-2208
- OSTI ID:
- 5277190
- Report Number(s):
- DOE/ET/32208-4
- Country of Publication:
- United States
- Language:
- English
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Vacuum deposited polycrystalline silicon films for solar cell applications. Quarterly report, September 15-December 31, 1979
Vacuum deposited polycrystalline silicon films for solar cell applications. Quarterly technical progress report No. 1, September 29-December 31, 1978
Related Subjects
36 MATERIALS SCIENCE
SILICON
VACUUM COATING
SILICON SOLAR CELLS
FABRICATION
PERFORMANCE
ALUMINIUM OXIDES
CARRIER DENSITY
DIFFUSION
DIFFUSION LENGTH
EFFICIENCY
FILL FACTORS
FILMS
GRAIN BOUNDARIES
GRAIN SIZE
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
MICROSTRUCTURE
PHOSPHORUS ADDITIONS
POLYCRYSTALS
SCANNING ELECTRON MICROSCOPY
SILVER
SPECTRAL RESPONSE
SUBSTRATES
TITANIUM
TITANIUM BORIDES
X-RAY DIFFRACTION
ALLOYS
ALUMINIUM COMPOUNDS
BORIDES
BORON COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALS
DEPOSITION
DIFFRACTION
DIRECT ENERGY CONVERTERS
ELECTRON MICROSCOPY
ELEMENTS
EQUIPMENT
METALS
MICROSCOPY
NONDESTRUCTIVE ANALYSIS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SCATTERING
SEMIMETALS
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SPECTROSCOPY
SURFACE COATING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture