Fabrication of self-organized InP nanopillars by ion-bombardment for optoelectronic applications

In this work, we investigate a wafer-scale, lithography-free, self-assembled indium phosphide (InP) nanopillars fabrication method based on ion bombardment. The influence of process conditions, such as the substrate temperature, ion beam energy, ion beam incidence angle, and processing time, were investigated with regard to the geometry (shape, diameter and height) and density of the fabricated nanopillars. For optimized process conditions, we show that by controlling the ion beam incidence angle (while rotating the sample), the shape (tapered to cylindrical) and average diameter (~75-150 nm) can be tuned and where InP nanopillar heights of ~600 nm were realized. It is shown that by modifying the shapes of the InP nanopillars, broadband anti-reflection can be obtained with average reflectance as low as ~4% in the wavelength range of 400-900 nm.