Field emission of uniform carbon cone arrays grown on porous silicon substrate

Uniform carbon cones arrays with average height of 1/spl mu/m were grown on porous silicon substrate using the hot filament chemical vapor deposition (HFCVD). Raman spectroscopy was used to characterize as-prepared carbon cones, which are composed of D peak (/spl sim/1352cm/sup -1/), G peak (-1601cm/sup -1/) and a broad peak at /spl sim/1475cm/sup -1/ attributed to hydrogenated carbon (a-C:H). It was found that both the immersion of porous silicon substrate in Fe/sub 2/(SO/sub 4/)/sub 3/ aqueous solution and the applied voltage in the deposition are vital to the growth of the carbon cones. Furthermore, the field emission properties of the as-prepared carbon cone arrays were studied, which shows an excellent field emission property. The threshold field is 2.2 V//spl mu/m, emission current of more than 80 /spl mu/A could be obtained as applied electric field is 3.4 V//spl mu/m. The internal-tip mechanism has been proposed for cone arrays in order to account for the observed field emission.