Fabrication of cone-shaped subwavelength structures by utilizing a confined convective self-assembly technique and inductively coupled-plasma reactive-ion etching

Abstract

Cone-shaped subwavelength structures (SWSs) were fabricated on a GaAs substrate by utilizing a confined convective self-assembly process followed by inductively coupled-plasma reactive-ion etching. A self-assembled polystyrene monolayer was used as an etch mask for pattern transfer onto the GaAs substrate. The fabricated SWS, having a cone profile with an aspect ratio of 1.5 and a 300 nm pitch, exhibited very low reflectance throughout the solar spectrum range and exhibited wide tolerance to different optical incidence angles. Reflectance of the cone-shaped SWS on the GaAs surface was less than 4% in a spectral range of 300–1000 nm under a normal incidence condition.