Correlating Light Absorption with Various Nanostructure Geometries in Vertically Aligned Si Nanowire Arrays

Exploring the interactions between light and nanostructures contributes greatly to understanding and engineering nanoscale optical phenomena related to device performance. However, this often involves a compromise between uniformity and scalability. Given that optical properties, and especially light absorption, are governed by the geometries of nanostructures, this study investigated the correlation between light absorption and vertically aligned silicon nanowire (v-SiNW) arrays synthesized using KrF stepper lithography. Controlled growth experiments of the v-SiNW arrays indicated that their geometrical parameters strongly influence their corresponding light absorption properties, as confirmed by reflection measurements and finite difference time domain (FDTD) simulations, which showed specific wavelength-dependent absorption. Moreover, the extent of tapering the v-SiNW arrays was modulating to achieve broad absorption of visible light resulting from the gradual change in diameter and to optimize their optical characteristics, based on diameter-dependent nanophotonic resonance, for use in various applications.