Patterned carbon nanotube (CNT) bundles were fabricated using thermal chemical vapor deposition (CVD) method. Patterns of different diameters and distances were defined on Si(100) substrates using photolithography. CNT bundle height was controlled using different acetylene (C2H2) flow times. The inter-bundle distance of CNTs to CNT bundle height ratio was maintained at approximately 2, a number predicted to have a maximum field emission for CNT, and left the patterned CNT bundle area as a variable parameter. The relationship between CNT bundle area and the field electron emission characteristics was studied. The lowest threshold electric field (E-th) of 0.7 V/mu m was obtained when the total area of patterned CNT bundles was approximately 46%. The result shows that there is an optimal CNT bundle area for electron field emission. (C) 2008 Elsevier B. V. All rights reserved.