Fabrication of sub-wavelength structures on silicon dioxide

In this reported work, nanosphere lithography (NSL) and inductively coupled plasma reactive ion etching (ICP-RIE) are combined to successfully fabricate a sub-wavelength structure (SWS) on a glass substrate, achieving broadband antireflection and increasing the transmittance of incident light through the glass. The experimental results show that the SWS surfaces with 180 nm width and 50 nm height could be fabricated onto glass. The mean reflectance of a blank glass is 5.81% in the wavelength range of 400-950 nm, 3 min of ICP-RIE combined with NSL reduce the mean reflectance to 3.5% and increases the mean transmittance from 92.3 to 94.3%. An additional coat of a 200 angstrom-thick gold layer on the 30 s etched surface sample reduces the transmittance in the visible light range (400-700 nm) to 36.6%, which is 2.25 times larger than that at the infrared range (700-950 nm). The proposed novel fabrication technology has the advantage of being low cost, and the fabricated nanodot array structure, which is gold coated, can be used on an insulated window.