Light harvesting of silicon nanostructure for solar cells application

Silicon nanostructures have light-harvesting effects for enhancing the performance of solar cells. Based on theoretical investigations on the optical properties of silicon nanowire (Si NW), the influencing laws of the size of Si NW on its light-harvesting effect are proposed. For the first time, we reveal that the resonant wavelength of Si NW predicted by the leaky mode theory does not correspond to the actual resonant wavelength calculated by the discrete dipole approximation method, but exactly coincides with the leftmost wavelength of the resonance peak. Then, the size dependency of the resonant intensity and width of Si NW is different from that of spherical nanoparticles, which can be deduced from the Mie theory. The size dependencies of resonant intensity and width are also applicative for silver/silicon composite nanowires. In addition, it is found that the harvested light by the Si and Ag/Si NW both show significant radial locality feature. The insight in this work is fundamental for the design and fabrication of efficient light -harvesting nanostructures for photovoltaic devices.