Si nanocone array was fabricated under oblique ion beam bombardment on diamond film-masked Si substrates at room temperature.SEM images of the ion sputtered samples showed that the Si nanocone density was determined by density of the diamond particles on the Si substrate

and topography of the Si nanocones was closely linked with the beam incidence.By increasing the incidence angle from 30° to 75°

apex angle of the Si nanocone decreased from 73° to 23°

and aspect ratio of the Si nanocone increased from 500 nm/360 nm to 2400 nm/600 nm.It was believed that the formation of silicon nanocones using the diamond film mask was attributed to the lower sputtering rate of diamond compared to Si substrate.With increasing incidence angle

the decreasing apex angle and increasing aspect ratio of Si nanocone were attributed to decreased effective diffusion coefficiency and increased sputtering yield induced by the ion beams.