Large-area and high-density silicon nanocone arrays by Ar+ sputtering at room temperature

The large-area, high-density of ∼1–2 × 109/cm2 silicon nanocone arrays by ion-irradiation with incident angle of 75° have been achieved by using carbon-cone-mask. The scanning electron microscopy (SEM) images show that the width of silicon nanocones is ∼150 nm and the height is ∼400 nm. The investigation of SEM shows that the formation of the silicon nanocones proceeds through three periods, carbon nanocones–nanocones with carbon on the top and silicon at the bottom-silicon nanocones.