Effects of etchant gas on the formation of carbon nanotip arrays grown by plasma-enhanced hot filament chemical vapor deposition

Carbon nanotip arrays were prepared from carbon films deposited on silicon by plasma-enhanced hot filament chemical vapor deposition using CH4, NH3 and H2 as reaction gases. The carbon films and arrays were investigated by atomic force microscopy, scanning electron microscopy and micro-Raman spectrometry. The results indicate that the formation of the carbon nanotip arrays greatly depends on the etchant gas ratio of NH3 to H2. The theory related to plasma and sputtering was applied to explain the formation of the carbon nanotip arrays under different gas ratios.