Fabrication of Disordered Nanostructures by Nanosphere Lithography and Its Application for Ultrathin Si Wafers

Abstract

Fabrication of the disordered Si nanostructure arrays with a controlled randomness has gained research interest because the well-controlled disorder can provide more effective light trapping. The parabolic Si nanostructures were made by combining processes of silica self-assembled monolayer deposition and reactive ion etching. We demonstrate that the order of the Si nanostructure arrays can be varied in the nanosphere lithography by blending two different silica nanoparticles of 960 nm and 520 nm in diameter. The order of the Si nanostructure arrays was adjusted by varying the fractions of the small size nanoparticles. The light trapping performances were analyzed by measuring the total reflectances from the textured wafers and also simulated using optical simulations. Furthermore, we incorporated our disordered Si nanostructure arrays on ultrathin Si wafers of a 50-um thickness, and the influence of the disorder on the optical performances was discussed.