Chemical vapor deposition of thin-film polycrystalline Si for low-cost solar cells. Third quarterly technical progress report, February 2, 1980-May 2, 1980

Technical Report · Thu May 01 00:00:00 EDT 1980

OSTI ID:6721735

Ruth, R P; Simpson, W I; Yang, J J.J.; Moudy, L A; Johnson, R E

The program has emphasized a study of the transport properties of p-type polycrystalline Si films as functions of average grain size and impurity doping concentration. Preliminary investigations of nucleation and early-stage growth phenomena in such films have also been carried out to provide improved understanding of the fundamental properties of the films that limit photovoltaic performance and thus to establish a good technical basis for subsequent attempts to achieve improved performance in solar cells using such films. Also, the study of transport properties was extended to n-type polycrystalline Si films. The transport studies have involved preparation of sets of B-doped p-type and P-doped n-type polycrystalline films grown simultaneously by SiH/sub 4/ pyrolysis in H/sub 2/ on polycrystalline high-purity alumina substrates in a range of average grain sizes (approx. 1 ..mu..m to approx. 125 ..mu..m) and with a range of impurity doping concentrations from approx. 10/sup 15/ to >10/sup 20/ cm/sup -3/, primarily at approx. 985/sup 0/C. The p-type films have been characterized in detail by measurements of transport properties of a function of sample temperature in the range 77 to 420/sup 0/K. The results of these investigations are described in detail. In particular, the height of the intergrain barrier in polycrystalline Si as a function of doping concentration as well as average grain size has been determined, and comparisons of these experimental results with the predictions of the grain-boundary trapping model for conduction in polycrystalline Si are made. Sets of CVD polycrystalline and single-crystal films have been used for the fabrication of solar cells, utilizing both vapor-grown and P-diffused junctions. The experimental solar cell structures have had generally poor photovoltaic properties, in most instances for easily diagnosed reasons.

• Research Organization: Rockwell International Corp., Anaheim, CA (USA). Electronic Devices Div.
• DOE Contract Number: AC03-79ET23045
• OSTI ID: 6721735
• Report Number(s): SAN-3045-3
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
SILICON
CHARGE TRANSPORT
CHEMICAL VAPOR DEPOSITION
CRYSTAL DOPING
SILICON SOLAR CELLS
FABRICATION
BORON ADDITIONS
CARRIER DENSITY
CARRIER MOBILITY
COST
DIFFUSION
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONS
EXPERIMENTAL DATA
FILMS
GRAIN SIZE
GRAPHS
HOLES
IMPURITIES
N-TYPE CONDUCTORS
P-TYPE CONDUCTORS
POLYCRYSTALS
SUBSTRATES
TEMPERATURE DEPENDENCE
TRAPPING
ALLOYS
BORON ALLOYS
CHEMICAL COATING
CRYSTAL STRUCTURE
CRYSTALS
DATA
DEPOSITION
DIRECT ENERGY CONVERTERS
ELEMENTARY PARTICLES
ELEMENTS
EQUIPMENT
FERMIONS
INFORMATION
LEPTONS
MATERIALS
MICROSTRUCTURE
MOBILITY
NUMERICAL DATA
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
SEMICONDUCTOR MATERIALS
SEMIMETALS
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture
360603 - Materials- Properties