Modeling and DLTS Analysis of Irradiated III-V Multijunction Solar Cells.
Final rept. Nov 84-Oct 85,
FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL ENGINEERING
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The objective of this research project was to develop a simple theoretical model based on Wilsons model to calculate the displacement damages introduced by either protron or electron irradiation in AlGaAs, GaAs, InGaAs and Ge. These calculations would then be applied to obtain an optimized triple junction solar cell structure using these materials with a specified end of life conversion efficiency. Empirical formulae and theoretical expressions were derived for calculating the displacement cross section, penetration depth, path length, total number of defects formed by an incident electron or protron, and the fractional loss of electron-hole pairs due to recombination loss. Formulae to calculate the degradation of short-circuit current under different electron and proton fluences and energies in AlGaAs, GaAs, InGaAs, Ge single junction solar cells and the triple junction cells formed from these materials were developed. The results of our calculations indicate that the degradation rate in each cell varies greatly, and depends critically not only the energy, fluence and the direction of the incident electrons and protons but also on the thickness of each cell in the triple junction cells. Major difficulties encountered in performing the theoretical calculations using the model developed in this report included may unknown parameters and the lack of experimental data on electron and proton damages in the AlGaAs and InGaAs solar cells for comparison with theoretical calculations. These uncertainties can be removed once the actual cell structures for the proposed triple junction cells are fabricated and measurements of radiation damage are made in these cells.
- *HOLES(ELECTRON DEFICIENCIES)
- *SOLAR CELLS
- *RADIATION DAMAGE
- CROSS SECTIONS
- SHORT CIRCUITS
- RECOMBINATION REACTIONS
- ELECTRIC CURRENT
- ELECTRON IRRADIATION
- Electric Power Production and Distribution
- Solid State Physics