Integrated photonic structures for light trapping in thin-film Si solar cells

Abstract

We explore the mechanisms for an efficient light trapping structure for thin-film silicon solar cells. The design combines a distributed Bragg reflector (DBR) and periodic gratings. Using photonic band theories and numerical simulations, we discover that light can be scattered into the DBR by gratings, with an unusual way of light trapping different from metal reflectors and photonic crystals. We further investigate the influence of DBR on generated photocurrent in different device configurations. These results would provide new design rules for photonic structures in thin-film solar cells.