Improved semiconductors for photovoltaic cells. Quarterly report No. 8, April 1-June 30, 1978
The main thrust of work has been the development of a Zn/sub 3/P/sub 2/ based, Schottky barrier solar cell with 5% AMI conversion efficiency. Transparent metal film devices, fabricated by sputter depositing magnesium, were evaluated. Sputter deposition was necessary to prepare air stable films with reproducible electrical and optical properties. The highest conversion efficiency achieved (no A-R) is 1.72%. An alternative, Schottky barrier grid device was devised to avoid the difficulties encountered with transparent metal films. Using relatively thick (2000 A) magnesium films and line spacing on the order of twice the nominal, a total area conversion efficiency of 6.08% was measured. Correcting for grid blockage yields an active area efficiency of 7.6%. The diffusion length of minority carriers had been measured for a large number of single crystal devices using a spectral response technique as well as a newly developed laser scanning method. Diffusion lengths as long as 9 ..mu..m have been found. An extensive study of metal semiconductor contacts of Zn/sub 3/P/sub 2/ has been made. A model recently advanced by Brillson, which correlates barrier height with the enthalpy of the reaction taking place at the metal semiconductor interface is in excellent agreement with the data. Thin films of Zn/sub 3/P/sub 2/ have been prepared by the close space transport method using muscovite mica as the substrate. The dependence of growth rate on temperature is that expected for an energy activated process. The activation energy deduced is in good agreement with the enthalpy of vaporization of Zn/sub 3/P/sub 2/. The grain size of the resulting films is of the order of 5 to 10 ..mu..m for 10 ..mu..m thick films.
- Research Organization:
- Delaware Univ., Newark (USA). Inst. of Energy Conversion
- DOE Contract Number:
- AC01-76ET20221
- OSTI ID:
- 7085120
- Report Number(s):
- COO-2460-8
- Country of Publication:
- United States
- Language:
- English
Similar Records
Improved semiconductors for photovoltaic cells. Quarterly report No. 7, January 1-March 31, 1978
Improved semiconductors for photovoltaic cells. Quarterly report No. 6, October 1-December 31, 1977
Related Subjects
36 MATERIALS SCIENCE
ZINC PHOSPHIDE SOLAR CELLS
DIFFUSION LENGTH
ELECTRIC CONTACTS
FABRICATION
ZINC PHOSPHIDES
VACUUM COATING
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EXPERIMENTAL DATA
FILMS
GRAIN SIZE
GRAPHS
LASERS
MAGNESIUM
MICA
OPTICAL PROPERTIES
OPTICAL SCANNERS
SCHOTTKY BARRIER DIODES
SPECTRAL RESPONSE
SPUTTERING
SUBSTRATES
ALKALINE EARTH METALS
CRYSTAL STRUCTURE
DATA
DEPOSITION
DIMENSIONS
DIRECT ENERGY CONVERTERS
ELECTRICAL EQUIPMENT
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
INFORMATION
LENGTH
METALS
MICROSTRUCTURE
MINERALS
NUMERICAL DATA
OPTICAL EQUIPMENT
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
ZINC COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture