Broadband antireflective Si nanopillar arrays produced by nanosphere lithography

In this work, we report an approach to fabricate Si nanopillar arrays by nanosphere lithography. With this method, the periods of Si arrays can be controlled by using different sized spheres. The produced Si arrays exhibit broadband antireflections, and the spectral positions with low reflection strongly depend on the periods of the arrays. Thus, the wavelength range of low reflection can be tuned by varying the period of Si array.