Analysis of Radiation Damaged and Annealed Gallium Arsenide and Indium Phosphide Solar Cells Using Deep Level Transient Spectroscopy.
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Power loss in spacecraft solar cells due to radiation damage was investigated. The mechanisms behind the degradation and based on deep-level defects in the crystalline lattice structure of the solar cell. Through a process known as Deep Transient Spectroscopy DLTS, a correlation can be made between damagerecovery and trap energy of the cell. Gallium GaAsGe and Indium Phosphide InP solar cells were subjected to 1 MeV electron irradiation, to fluences of 1E16 electronssq cm. Attempts at recovery included thermal annealing, alone, and with an applied forward bias current, and injection annealing. Various cycles of irradiation, annealing and DLTS were performed, in an attempt to correlate damage to trap energy level and growth. The results show that DLTS cannot be performed on GaAsGe, and no recovery was apparent in these cells. DLTS analysis of InP indicated excellent photoinjection annealing recovery at a variety of temperatures. Lower energy level defects are associated with the recovery of the cells while the higher energy traps are indicative of permanent degradation in the Inp solar cells. Applying this information to future research could increase satellite mission life, and significantly reduce space mission costs. Radiation damage in solar cells, DLTS, Annealing, Heterojunction, Gallium arsenide, Indium phosphide.
- *GALLIUM ARSENIDES
- *INDIUM PHOSPHIDES
- *RADIATION DAMAGE
- *SOLAR CELLS
- ARTIFICIAL SATELLITES
- ELECTRON IRRADIATION
- ENERGY LEVELS
- SPACE MISSIONS
- CRYSTAL LATTICES
- Nuclear Radiation Shielding, Protection and Safety
- Electric Power Production and Distribution
- Atomic and Molecular Physics and Spectroscopy