THE CONTROL OF RADIATION-RESISTANCE IN-SPACE SOLAR-CELLS

Solar cells, powering satellites and other space vehicles, can suffer substantial degradation in performance by electron and proton irradiat ion experienced in orbit. These effects are first described, and the b ehaviour of silicon solar cells compared with cells of gallium arsenid e and indium phosphide, and the more recent thin film type cells. In p articular, the paper will discuss the phenomenon of 'photon degradatio n' in silicon cells, and recent progress in understanding the defect m echanisms responsible for this effect occurring after illumination of irradiated cells. Strategies for improving the radiation resistance of silicon solar cells, including the use of 'defect gettering' will be discussed, while the effects of annealing radiation damage will be out lined. Finally, the paper will seek to identify areas where an improve d understanding of defect behaviour is necessary to produce further im provements in performance. In particular, it highlights the need for f undamental studies of advanced solar cell structures and materials, in cluding CIS cells, where significant improvement in radiation toleranc e has been found.