High performance and radiation-resistance of GaAs-on-Si solar cells with novel structures

Multi-junction (MJ) solar cells on Si substrates are expected as low-cost and high-efficiency cells. Previously, the authors have demonstrated that GaAs-on-Si solar cells with novel structures have better radiation-resistance than GaAs and single-crystal Si space cells. In this paper, effectiveness; of novel structures such as super-lattice, strained super-lattice and Bragg reflectors upon initial performance and radiation-resistance of GaAs-on-Si cells has been studied. GaAs-on-Si cells with Bragg reflectors are found to have better radiation-resistance than those without Bragg reflectors. Insertion of super-lattice and strained super-lattice has also been found to be effective for improving initial cell performance as a result of effects of dislocation annihilation and back-surface field layer by insertion of such layers.