Low cost synthesis of silicon nanowires for photonic applications

Achieving light management in nanostructured materials is a recent challenge of great resonance among the scientific community, which is generally attained by expensive surface patterning requiring advanced technologies. In this paper, we report the realization of 2D random fractal arrays of silicon nanowires (NWs) synthesized with a low cost approach compatible with Si technology, without the use of any lithography or mask. Their innovative photonic properties are exploited in comparison to non-fractal nanowires. In particular, a remarkable room temperature luminescence is attained in Si NWs due to quantum confinement effect. The NWs fabrication was engineered in order to produce two-dimensional random fractal arrays of Si NWs whose structural properties were investigated and compared to other non-fractal Si NW systems. The impressive light trapping and strongly enhanced Raman signal of our fractal Si NW array is of significant interest for potential applications spanning from photonics, to photovoltaics and sensing.