Controlled evolution of silicon nanocone arrays induced by Ar+ sputtering at room temperature, using the coating carbon as a mask, is demonstrated. The investigation of scanning electron microscopy indicates that the morphology of silicon nanostructures can be controlled by adjusting the thickness of the coating carbon film. Increasing the thickness of the coating carbon film from 50–60 nm, 250–300 nm and 750–800 nm to 1500 nm, the morphologies of silicon nanostructures are transformed from smooth surface ripple, coarse surface ripple and surface ripple with densely distributed nanocones to nanocone arrays with a high density of about 1 × 109 – 2 × 109 cm−2.

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.

In this paper, effect of pressure on deposition temperature for hot filament chemical vapor deposition of diamond thin films was investigated. SEM images show that diamond film of small grain size can be deposited at 500°C by decreasing the pressure from 5.32 kPa to 0.67 kPa. Raman spectra show that the quality of the film deposited at 0.67 kPa and 500°C was as good as that of the film deposited at 5.32 kPa and 700°C. We believe that the deposition of diamond film at low temperature and low pressure is due to the effect of pressure on the concentrations and kinetic energy of the active species near the substrate surface. Compared to the situations with higher pressure, the active species at 0.67 kPa arrive at the substrate surface with higher concentration, which makes it possible for the high-quality diamond films of small grain size can be deposited at very low temperature (500°C).