We synthesized a highly aligned conical Si array on Si(100) for a field electron emitter by plasma-enhanced chemical vapor deposition (PECVD). The number density of these submicron Si cones was controlled in the range 10(6)-10(9) cm(-2). The 10(6) cm(-2) conical Si array exhibited a low threshold voltage for its field electron emission, while for an array with a high number density, the emission property was degraded due to the electric field screening effect. (C) 2004 Elsevier B.V. All rights reserved.