Improved semiconductors for photovoltaic cells. Quarterly report No. 9, July 1-September 1, 1978

Technical Report · Sun Jan 01 00:00:00 EST 1978

DOI:https://doi.org/10.2172/7085103· OSTI ID:7085103

Device related work has been directed toward the development of effective single and double layer antireflection coatings for Zn/sub 3/P/sub 2/. The reflectivity of bare Zn/sub 3/P/sub 2/. The reflectivity of bare Zn/sub 3/P/sub 2/ as well as SiO, Ta/sub 2/O/sub 5/, MgF/sub 2//ZnS and SiO/sub 2//ZnS coated samples have been measured. Reflection losses have been reduced to 5 to 6% with double layer Ar coatings. The experimental reflectivity integrated over the photon flux distribution yields a maximum J/sub SC/ = 26.5 ma/cm/sup 2/ for AM1.5 insolation (83.2 mW/cm/sup 2/). Theoretical modeling of the Schottky barrier grid device was begun in order to establish the relationship between collection efficiency, device geometry and minority carrier diffusion length. The study of the barrier height of metal/Zn/sub 3/P/sub 2/ junctions has been completed. Barrier height is particularly sensitive to surface damage such as that incurred during glow discharge cleaning. Thin polycrystalline films are now entering the device development stage. Chemical polishing of the surface of thin films with bromine-methanol yields surfaces suitable for photolithography. Devices however, have extremely high series resistance due to the high sheet resistance of the film. A multilayer substrate has been developed which is promising. It consists of mica which acts as a mechanical support and has the proper coefficient of expansion, a thin film of iron or slver which makes for low sheet resistance and a carbon film cover which makes ohmic contact to Zn/sub 3/P/sub 2/ and effectively acts as a diffusion barrier.

• Research Organization: Delaware Univ., Newark (USA). Inst. of Energy Conversion
• DOE Contract Number: AC01-76ET20221
• OSTI ID: 7085103
• Report Number(s): COO-2460-9
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
ZINC PHOSPHIDE SOLAR CELLS
ANTIREFLECTION COATINGS
FABRICATION
ZINC PHOSPHIDES
VACUUM COATING
CHEMICAL POLISHING
DIFFUSION LENGTH
EFFICIENCY
FILMS
MAGNESIUM FLUORIDES
MICA
POLYCRYSTALS
RESEARCH PROGRAMS
SILICON OXIDES
SUBSTRATES
TANTALUM OXIDES
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COATINGS
CRYSTALS
DEPOSITION
DIMENSIONS
DIRECT ENERGY CONVERTERS
EQUIPMENT
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LENGTH
MAGNESIUM COMPOUNDS
MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
POLISHING
SILICON COMPOUNDS
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
SURFACE FINISHING
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture