Enhanced Optical Absorption of Dual-Diameter Structured Silicon Nanoholes Array

The optical properties have been numerically investigated in crystalline silicon nanoholes array for various structural parameters. We have demonstrated that the light absorption can be greatly enhanced in silicon nanoholes array especially for long wavelength absorption compared with single diameter nanoholes array. We have also obtained the optimal parameters for absorption wavelength control, at which the photocurrent enhancement factors have been achieved to be 14.43% compared to silicon thin film. Furthermore, the underlying mechanism of the absorption enhancement in dual-diameter nanoholes array has been discussed.