An embedded nanosphere dielectric structure on an a-Si ultrathin film improves weighted absorption from 23.8% to 39.9%. The PMMA embedding layer offers a guided wave mode as well as mechanical robustness, in addition to the resonant whispering gallery modes coupling. Broadband light-trapping enhancements are observed by dielectric surface textured structures of hemispheres, nanocones, nanospheres, or embedded nanospheres.
- photonic crystals
- whispering gallery modes