Linear length-dependent light-harvesting ability of silicon nanowire

Silicon nanowire (SiNW) is of great promising for photovoltaic applications due to its excellent performance in light-harvesting. Some experimental and theoretical results indicate its light-harvesting is dramatically length dependent, while there is still no investigation on this dependency. Through reliable simulations on the optical extinction and absorption spectra of SiNWs with varying lengths, we find that the light-harvesting ability of SiNW is linear with its length. For the SiNWs of the optimal diameter, 80 nm, the linearity between the light-concentration (light-absorption) multiples and length is about 133 μm−1 (50 μm−1). This linear relationship can be explained reasonably by the leaky modes theory.