Vacuum deposited polycrystalline silicon films for solar cell applications. Final report, 29 September 1978-30 September 1979

Technical Report · Sat Dec 01 04:00:00 EST 1979

OSTI ID:5277190

Feldman, C; Satkiewicz, F G; Blum, N A

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.
• OSTI ID: 5277190
• Report Number(s): DOE/ET/32208-4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BORIDES
BORON COMPOUNDS
CARRIER DENSITY
CHALCOGENIDES
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALS
DEPOSITION
DIFFRACTION
DIFFUSION
DIFFUSION LENGTH
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRON MICROSCOPY
ELEMENTS
EQUIPMENT
FABRICATION
FILL FACTORS
FILMS
GRAIN BOUNDARIES
GRAIN SIZE
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
METALS
MICROSCOPY
MICROSTRUCTURE
NONDESTRUCTIVE ANALYSIS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
PHOSPHORUS ADDITIONS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
POLYCRYSTALS
SCANNING ELECTRON MICROSCOPY
SCATTERING
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SILVER
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SPECTRAL RESPONSE
SPECTROSCOPY
SUBSTRATES
SURFACE COATING
TITANIUM
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VACUUM COATING
X-RAY DIFFRACTION