Patent ID: 7718223

Claim:
A method for controlling density of an array of carbon nanotubes, referred to as “CNTs,” in two or more regions of a substrate, the method comprising: providing a substrate, having a selected catalyst region suitable for growth of CNTs; providing a designation of a first range and a second range of CNT densities for a first CNT growth region and for a second CNT growth region, respectively, on the substrate, where the second CNT growth region is spaced apart from the first CNT growth region; heating the substrate to a first temperature T 1 lying in a first CNT growth temperature range; locally heating the second CNT growth region, but not the first CNT growth region, to a second temperature T 2 , substantially greater than T 1 and lying in a second CNT growth temperature range; and exposing the substrate to a source of C m H n molecules, for selected positive numbers m and n, permitting a CNT array having approximately a first average density ρ1 within the first density range to grow in the first region, and permitting a CNT array having approximately a second average density ρ2 within the second density range to grow in the second region, where ρ1 differs substantially from ρ2.